Abstract in English:Mycobacterium bovis is the main causative agent of animal tuberculosis (TB) and it may cause TB in humans. Molecular typing of M. bovis isolates provides precise epidemiological data on issues of inter- or intra-herd transmission and wildlife reservoirs. Techniques used for typing M. bovis have evolved over the last 2 decades, and PCR-based methods such as spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) have been extensively used. These techniques can provide epidemiological information about isolates of M. Bovis that may help control bovine TB by indicating possible links between diseased animals, detecting and sampling outbreaks, and even demonstrating cases of laboratory cross-contamination between samples. This review will focus on techniques used for the molecular typing of M. bovis and discuss their general aspects and applications.
Abstract in English:Agro-industrial wastes have been used as substrate-support in solid state fermentation for enzyme production. Molasses and sugarcane bagasse are by-products of sugar industry and can be employed as substrates for invertase production. Invertase is an important enzyme for sweeteners development. In this study, a xerophilic fungus Aspergillus niger GH1 isolated of the Mexican semi-desert, previously reported as an invertase over-producer strain was used. Molasses from Mexico and Cuba were chemically analyzed (total and reducer sugars, nitrogen and phosphorous contents); the last one was selected based on chemical composition. Fermentations were performed using virgin and hydrolyzate bagasse (treatment with concentrated sulfuric acid). Results indicated that, the enzymatic yield (5231 U/L) is higher than those reported by other A. niger strains under solid state fermentation, using hydrolyzate bagasse. The acid hydrolysis promotes availability of fermentable sugars. In addition, maximum invertase activity was detected at 24 h using low substrate concentration, which may reduce production costs. This study presents an alternative method for invertase production using a xerophilic fungus isolated from Mexican semi-desert and inexpensive substrates (molasses and sugarcane bagasse).
Abstract in English:This study aimed the optimization of culture condition and composition for production of Cryptococcus laurentii 11 biomass and lipids in cheese whey medium supplemented with sugarcane molasses. The optimization of pH, fermentation time, and molasses concentration according to a full factorial statistical experimental design was followed by a Plackett-Burman experimental design, which was used to determine whether the supplementation of the culture medium by yeast extract and inorganic salts could provide a further enhancement of lipids production. The following conditions and composition of the culture medium were found to optimize biomass and lipids production: 360 h fermentation, 6.5 pH and supplementation of (g L-1): 50 molasses, 0.5 yeast extract, 4 KH2PO4, 1 Na2HPO4, 0.75 MgSO4•7H2O and 0.002 ZnSO4•H2O. Additional supplementation with inorganic salts and yeast extract was essential to optimize the production, in terms of product concentration and productivity, of neutral lipids by C. laurentii 11. Under this optimized condition, the production of total lipids increased by 133% in relation to control experiment (from 1.27 to 2.96 g L-1). The total lipids indicated a predominant (86%) presence of neutral lipids with high content of 16- and 18- carbon-chain saturated and monosaturated fatty acids. This class of lipids is considered especially suitable for the production of biodiesel.
Abstract in English:Proteolysis-resistant lipases can be well exploited by industrial processes which employ both lipase and protease as biocatalysts. A proteolysis resistant lipase from Bacillus pumilus SG2 was isolated, purified and characterized earlier. The lipase was resistant to native and commercial proteases. In the present work, we have characterized the lip gene which encodes the proteolysis-resistant lipase from Bacillus pumilus SG2. The parameters and structural details of lipase were analysed. The lip gene consisted of 650 bp. The experimental molecular weight of SG2 lipase was nearly double that of its theoretical molecular weight, thus suggesting the existence of the functional lipase as a covalent dimer. The proteolytic cleavage sites of the lipase would have been made inaccessible by dimerisation, thus rendering the lipase resistant to protease.
Abstract in English:Polyhydroxyalkanoates (PHAs) can be produced by microorganisms and are a biodegradable alternative to fossil-fuel based plastics. Currently, the focus is on reducing production costs by exploring alternative substrates for PHAs production, and on producing copolymers which are less brittle than monomers. Accordingly, this study used a substrate consisting of wastewater from waste-glycerol fermentation, supplemented with different amounts of acetic and propionic acids. These substrates were used to feed mixed microbial communities enriched from activated sludge in a sequencing batch reactor. A reactor supplemented with 2 mL of acetic acid produced 227.8 mg/L of a homopolymer of hydroxybutyrate (3HB); 4 mL of acetic acid produced 279.8 mg/L 3HB; whereas 4 mL of propionic acid produced 673.0 mg/L of a copolymer of 3HB and 3HV (hydroxyvalerate). Ribosomal Intergenic Spacer Analysis (RISA) was used to show the differences between the communities created in the reactors. Thauera species predominated in biomass that produced 3HB; Paracoccus denitrificans in the biomass that produced 3HB-co-3HV. Because P. denitrificans produced the more desirable copolymer, it may be advantageous to promote its growth in PHAs-producing reactors by adding propionate.
Abstract in English:The chemical screening carried out on Schizochytrium sp. biomass led the identification of 24 types of organic compounds belonging to n-alkanes, 1-alkenes, 1-alkanols, free fatty acids, methyl and ethyl esters of saturated and unsaturated fatty acids, saturated tri- and diglycerides, unsaturated monoglycerides, wax esters, sterols, triterpenes, and mono- and sesquiterpenes. Moreover, a sample containing fully saturated ethyl biodiesel was obtained experimentally with a yield of 28.72% w/w of the crude extract, and an average chain length of 15.52 carbons. This strain produced no toxins, but showed important nutrients, making it potentially applicable to the field of functional food, and biodiesel production.
Abstract in English:The aims of this work was to characterise indigenous Saccharomyces cerevisiae strains in the naturally fermented juice of grape varieties Cabernet Sauvignon, Grenache, Tempranillo, Sauvignon Blanc and Verdejo used in the São Francisco River Valley, northeastern Brazil. In this study, 155 S. cerevisiae and 60 non-Saccharomyces yeasts were isolated and identified using physiological tests and sequencing of the D1/D2 domains of the large subunit of the rRNA gene. Among the non-Saccharomyces species, Rhodotorula mucilaginosa was the most common species, followed by Pichia kudriavzevii, Candida parapsilosis, Meyerozyma guilliermondii, Wickerhamomyces anomalus, Kloeckera apis, P. manshurica, C. orthopsilosis and C. zemplinina. The population counts of these yeasts ranged among 1.0 to 19 x 10(5) cfu/mL. A total of 155 isolates of S. cerevisiae were compared by mitochondrial DNA restriction analysis, and five molecular mitochondrial DNA restriction profiles were detected. Indigenous strains of S. cerevisiae isolated from grapes of the São Francisco Valley can be further tested as potential starters for wine production.
Abstract in English:Contaminated environments have a large number of bacteria which can accumulate PHA as their energy reserves. Out of 54 isolated bacterial strains from three groups of contaminated sites 48 were found PHA positive. The sites were grouped on the basis of the type of carbon sources i.e. sugars, fatty acids and much diverse type. Strains MFD5, MFD11, UML3, USL2, SEL2, SEL3, SEL10 and PFW1 produced 69.9 ± 0.29, 75.27 ± 0.45, 65.43 ± 0.1, 72.54 ± 0.27, 76.61 ± 0.28, 61.81 ± 0.05, 71.16 ± 0.09 and 74.92 ± 0.5 percent of PHA to their constant cell weight (CCW) respectively in PHA detection media supplemented with 2% glucose. Molasses, whey, crumbs hydrolysate and palm oil were checked as inexpensive carbon sources. Molasses alone could supply the required nutrients for growth and PHA production. Strain SEL2 produced 47.36 ± 0.45% PHA using 2% molasses at 37 °C and pH 7.0. Upon production optimization the best accumulation (80.95 ± 0.01%) was observed in PHA detection media with 0.2% nitrogen source, 3% molasses, pH 5.0 and 37 °C by the strain SEL2. The overall effect of the presence of increased molasses concentration in the media was positive it increased the accumulation period till 72 h. Enterobacter sp. SEL2 (JF901810) is first time being reported for PHA production.
Abstract in English:Growth associated biosynthesis of medium chain length poly-3-hydroxyalkanoates (mcl-PHA) in Pseudomonas putida Bet001 isolated from palm oil mill effluent was studied. Models with substrate inhibition terms described well the kinetics of its growth. Selected fatty acids (C8:0 to C18:1) and ammonium were used as carbon and nitrogen sources during growth and PHA biosynthesis, resulting in PHA accumulation of about 50 to 69% (w/w) and PHA yields ranging from 10.12 g L-1 to 15.45 g L-1, respectively. The monomer composition of the PHA ranges from C4 to C14, and was strongly influenced by the type of carbon substrate fed. Interestingly, an odd carbon chain length (C7) monomer was also detected when C18:1 was fed. Polymer showed melting temperature (Tm) of 42.0 (± 0.2) °C, glass transition temperature (Tg) of -1.0 (± 0.2) °C and endothermic melting enthalpy of fusion (ΔHf) of 110.3 (± 0.1) J g-1. The molecular weight (Mw) range of the polymer was relatively narrow between 55 to 77 kDa.
Abstract in English:The time courses for production of fungal biomass, lipid, phenolic and arachidonic acid (ARA) as well as expression of the genes involved in biosynthesis of ARA and lipid were examined in Mortierella alpina CBS 754.68. A significant increase in the arachidonic acid content in lipids that coincided with reduced levels of lipid was obtained. Reduced gene expression occurred presumably due to the steady reduction of carbon and nitrogen resources. However, these energy resources were inefficiently compensated by the breakdown of the accumulated lipids that in turn, induced up-regulated expression of the candidate genes. The results further indicated that the expression of the GLELO encoding gene is a rate-limiting step in the biosynthesis of ARA in the early growth phase.
Abstract in English:The interest in production of natural colorants by microbial fermentation has been currently increased. The effects of D-glucose concentration (3.18-36.82 g/L), inoculum size (12.5 x 10(9)-49.5 x 10(9) cfu cells/mL) and air-flow rate (1.95-12.05 L/L min) on the biomass, total carotenoid and canthaxanthin (CTX) accumulation of Dietzia natronolimnaea HS-1 in a batch bioreactor was scrutinized using a response surface methodology-central composite rotatable design (RSM-CCRD). Second-order polynomial models with high R² values ranging from 0.978 to 0.990 were developed for the studied responses using multiple linear regression analysis. The models showed the maximum cumulative amounts of biomass (7.85 g/L), total carotenoid (5.48 mg/L) and CTX (4.99 mg/L) could be achieved at 23.38 g/L of D-glucose, 31.2 x 10(9) cfu cells/mL of inoculation intensity and air-flow rate of 7.85 L/L min. The predicted values for optimum conditions were in good agreement with experimental data.
Abstract in English:The main objective of this study was production of ethanol from three lignocellulosic biomasses like sugarcane bagasse, rice straw and wheat straw by Sacchromyces cervisae. All the three substrates were ground to powder form (2 mm) and pretreated with 3%H2O2 + 2% NaOH followed by steaming at 130 °C for 60 min. These substrates were hydrolyzed by commercial cellulase enzyme. The whole fermentation process was carried out in 500 mL Erlenmeyer flask under anaerobic conditions in submerged fermentation at 30 °C for three days of incubation period. FTIR analysis of the substrates indicated significant changes in the alteration of the structure occurred after pretreatment which leads to efficient saccharification. After pretreatment the substrates were hydrolyzed by commercial cellulase enzyme and maximum hydrolysis was observed in sugarcane bagasse (64%) followed by rice straw (40%) and wheat straw (34%). Among all these tested substrates, sugarcane bagasse (77 g/L) produced more ethanol as compared to rice straw (62 g/L) and wheat straw (44 g/L) using medium composition of (%) 0.25 (NH4)2SO4, 0.1 KH2PO4, 0.05 MgSO4, 0.25 Yeast extract by S. cervisae.
Abstract in English:The research evaluated the interactions of two main factors (strain / types of spawn) on various parameters with the purpose to assess its effect on yield and biochemical composition of Lentinula edodes fruiting bodies cultivated on pasteurized wheat straw. The evaluation was made with four strains (IE-40, IE-105, IE-124 and IE-256). Different types of spawns were prepared: Control (C) (millet seed, 100%), F1 (millet seed, 88.5%; wheat bran, 8.8%; peat moss, 1.3%; and CaS0(4), 1.3%) and F2 (the same formula as F1, but substituting the wheat bran with powdered wheat straw). Wheat straw was pasteurized by soaking it for 1 h in water heated to 65 °C. After this the substrate (2 kg wet weight) was placed in polypropylene bags. The bags were inoculated with each spawn (5% w/w) and incubated in a dark room at 25 °C. A proximate analysis of mature fruiting bodies was conducted. The mean Biological Efficiency (BE) varied between 66.0% (C-IE-256) and 320.1% (F1-IE-124), with an average per strain of 125.6%. The highest mean BE was observed on spawn F1 (188.3%), significantly different from C and F2. The protein content of fruiting bodies was high, particularly in strain IE-40-F1 (17.7%). The amount of fat varied from 1.1 (F1-IE-40) to 2.1% (F2-IE-105) on dry matter. Carbohydrates ranged from 58.8% (F1-IE-40) to 66.1% (F1-IE-256). The energy value determined ranged from 302.9 kcal (F1-IE-40) to 332.0 kcal (F1-IE-256). The variability on BE observed in this study was significantly influenced by the spawn's formulation and genetic factors of the different strains.
Abstract in English:Pichia pastoris is methylotrophic yeast used as an efficient expression system for heterologous protein production. In order to evaluate the effects of temperature (10 and 30 °C) and methanol (1 and 3% (v/v)) on genetically-modified Pichia pastoris, different biomarkers were evaluated: Heat stress (HSF-1 and Hsp70), oxidative stress (OGG1 and TBARS) and antioxidant (GLR). Three yeast cultures were performed: 3X = 3% methanol-10 °C, 4X = 3% methanol-30 °C, and 5X = 1% methanol-10°C. The expression level of HIF-1α, HSF-1, HSP-70 and HSP-90 biomarkers were measured by Western blot and in situ detection was performed by immunocytochemistry. Ours results show that at 3% methanol -30 °C there is an increase of mitochondrial OGG1 (mtOGG1), Glutathione Reductase (GLR) and TBARS. In addition, there was a cytosolic expression of HSF-1 and HSP-70, which indicates a deprotection against nucleolar fragmentation (apoptosis). On the other hand, at 3% methanol -10 °C and 1% and at methanol -10 °C conditions there was nuclear expression of OGG1, lower levels of TBARS and lower expression of GLR, cytosolic expression of HSF-1 and nuclear expression HSP-70. In conclusion, our results suggest that 3% methanol-30 °C is a condition that induces a strong oxidative stress and risk factors of apoptosis in modified-genetically P. pastoris.
Abstract in English:Pichia pastoris is a methylotrophic yeast used as an efficient expression system for heterologous protein production as compared to other expression systems. Considering that every cell must respond to environmental changes to survive and differentiate, determination of endogenous protein related to heat stress responses and hypoxia, it would necessary to establish the temperature and methanol concentration conditions for optimal growth. The aim of this study is characterize the culture conditions through the putative biomarkers in different conditions of temperature and methanol concentration. Three yeast cultures were performed: 3X = 3% methanol -10 °C, 4X = 3% methanol -30 °C, and 5X = 1% methanol -10 °C. The expression level of HIF-1α, HSF-1, HSP-70 and HSP-90 biomarkers were measured by Western blot and in situ detection was performed by immunocytochemistry. The western blot results of HIF-1α and HSP-90 did not indicate statistically significant in the culture conditions studied. Respect to biomarkers location, HIF-1α and HSP-90 presented differences between cultures. In conclusion, the results suggest the cultures in a hypoxic condition produce a high density and yeast cells smaller. Beside the high density would not necessary related with a high production of recombinant proteins in modified-genetically P. pastoris.
Abstract in English:Yeasts can be enriched with microelements, including iron; however, special physicochemical conditions are required to formulate a culture media that promotes both yeast growth and iron uptake. Different iron sources do not affect biomass formation; however, considering efficacy, cost, stability, and compatibility with Saccharomyces cerevisiae metabolism, ferrous sulphate is recommended.
Abstract in English:P. aeruginosa and Acinetobacter spp. are important pathogens associated with late nosocomial pneumonia in hospitalized and institutionalized individuals. The oral cavity may be a major source of these respiratory pathogens, particularly in the presence of poor oral hygiene and periodontal infection. This study investigated the prevalence of P. aeruginosa and Acinetobacter spp. in subgingival biofilm and saliva of subjects with periodontal disease or health. Samples were obtained from 55 periodontally healthy (PH) and 169 chronic periodontitis (CP) patients. DNA was obtained from the samples and detection of P. aeruginosa and Acinetobacter spp. was carried out by multiplex and nested PCR. P. aeruginosa and Acinetobacter spp. were detected in 40% and 45% of all samples, respectively. No significant differences in the distribution of these microorganisms between men and women, subgingival biofilm and saliva samples, patients < 35 and > 35 years of age, and smokers and non-smokers were observed regardless periodontal status (p > 0.05). In contrast, the frequencies of P. aeruginosa and Acinetobacter spp. in saliva and biofilm samples were significantly greater in CP than PH patients (p < 0.01). Smokers presenting P. aeruginosa and high frequencies of supragingival plaque were more likely to present CP than PH. P. aeruginosa and Acinetobacter spp. are frequently detected in the oral microbiota of CP. Poor oral hygiene, smoking and the presence of P. aeruginosa are strongly associated with periodontitis.
Abstract in English:In this study we attempted to modify the PCR-RFLP method using restriction enzyme MwoI for the identification of medically important Aspergillus species. Our subjects included nine standard Aspergillus species and 205 Aspergillus isolates of approved hospital acquired infections and hospital indoor sources. First of all, Aspergillus isolates were identified in the level of species by using morphologic method. A twenty four hours culture was performed for each isolates to harvest Aspergillus mycelia and then genomic DNA was extracted using Phenol-Chloroform method. PCR-RFLP using single restriction enzyme MwoI was performed in ITS regions of rDNA gene. The electrophoresis data were analyzed and compared with those of morphologic identifications. Total of 205 Aspergillus isolates included 153 (75%) environmental and 52 (25%) clinical isolates. A. flavus was the most frequently isolate in our study (55%), followed by A. niger 65(31.7%), A. fumigatus 18(8.7%), A. nidulans and A. parasiticus 2(1% each). MwoI enabled us to discriminate eight medically important Aspergillus species including A. fumigatus, A. niger, A. flavus as the most common isolated species. PCR-RFLP method using the restriction enzyme MwoI is a rapid and reliable test for identification of at least the most medically important Aspergillus species.
Abstract in English:The aim of this study was to investigate the phylogenetic background and to assess hlyD (involved in the secretion of haemolysin A) and intll (encoding a class 1 integrase) in Escherichia coli isolates derived from urinary and fecal specimens. A total of 200 E. coli isolates was collected from patients presenting with urinary tract infection (UTI) during September 2009 to September 2010 and screened for hlyD and intll genes by polymerase chain reaction (PCR). Phylogenetic analysis showed that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D) and that uropathogenic E. coli (UPEC) isolates mainly belong to groups B2 (54%) and D (34%) whereas group A (44%) and D (26%) are predominant among commensal E. coli isolates. In this study, hlyD was present in 26% of UPEC and 2% of commensal E. coli isolates. However, hemolytic activity was detected for 42% of UPEC and 6% of commensal E. coli isolates (p < 0.05). intll gene was more frequently expressed in UPEC (24%) in comparison with commensal E. coli isolates (12%). Resistance to aztreonam, co-trimoxazole and cefpodoxime were frequently found among UPEC isolates whereas commensal E. coli isolates were commonly resistant to co-trimoxazole, nalidixic acid and cefotaxime. Concluding, a considerable difference between UPEC and commensal E. coli isolates was observed regarding their phylogenetic groups, presence of class 1 integron and hlyD gene, hemolysin activity and resistance pattern. The detection of class 1 integrons and hlyD gene was higher among UPEC compared with commensal E. coli isolates. These findings may contribute for a better understanding of the factors involved in the pathogenesis of UPEC.
Abstract in English:Microbial culture collections underpin biotechnology applications and are important resources for clinical microbiology by supplying reference strains and/or performing microbial identifications as a service. Proteomic profiles by MALDI-TOF MS have been used for Candida spp. identification in clinical laboratories and demonstrated to be a fast and reliable technique for the routine identification of pathogenic yeasts. The main aim of this study was to apply MALDI-TOF MS combined with classical phenotypic and molecular approaches to identify Candida clinical isolates preserved from 1 up to 52 years in a Brazilian culture collection and assess its value for the identification of yeasts preserved in this type of collections. Forty Candida spp. clinical isolates were identified by morphological and biochemical analyses. Identifications were also performed by the new proteomic approach based on MALDI-TOF MS. Results demonstrated 15% discordance when compared with morphological and biochemical analyses. Discordant isolates were analysed by ITS sequencing, which confirmed the MALDI-TOF MS identifications and these strains were renamed in the culture collection catalogue. In conclusion, proteomic profiles by MALDI-TOF MS represents a rapid and reliable method for identifying clinical Candida species preserved in culture collections and may present clear benefits when compared with the performance of existing daily routine methods applied at health centres and hospitals.
Abstract in English:Emergence of drug-resistant strains has demanded for alternative means of combating fungal infections. Oils of Carum copticum and Thymus vulgaris have long been used in ethnomedicine for ailments of various fungal infections. Since their activity has not been reported in particular against drug-resistant fungi, this study was aimed to evaluate the effects of oils of C. copticum and T. vulgaris on the growth and virulence of drug-resistant strains of Aspergillus spp. and Trichophyton rubrum. The gas chromatography-mass spectrometry analysis revealed thymol constituting 44.71% and 22.82% of T. vulgaris and C. copticum, respectively. Inhibition of mycelial growth by essential oils was recorded in the order of thymol > T. vulgaris > C. copticum against the tested strains. RBC lysis assay showed no tested oils to be toxic even up to concentration two folds higher than their respective MFCs. Thymol exhibited highest synergy in combination with fluconazole against Aspergillus fumigatus MTCC2550 (FICI value 0.187) and T. rubrum IOA9 (0.156) as determined by checkerboard method. Thymol and T. vulgaris essential oil were equally effective against both the macro and arthroconidia growth (MIC 72 µg/mL). A > 80% reduction in elastase activity was recorded for A. fumigatus MTCC2550 by C. copticum, T. vulgaris oils and thymol. The effectiveness of these oils against arthroconidia and synergistic interaction of thymol and T. vulgaris with fluconazole can be exploited to potentiate the antifungal effects of fluconazole against drug-resistant strains of T. rubrum and Aspergillus spp.
Abstract in English:Brucella is an intracellular pathogen capable of infecting animals and humans. The aim of this study was to identify Brucella spp in sera of high risk individuals by a polymerase chain reaction (PCR)-based method. A total of 180 patients suspected to have Brucellosis were examined by serological tests. To establish a PCR protocol for diagnosis of active brucellosis, DNA was extracted from the serum samples by using a commercial kit. PCR amplification was done for detection of Brocella DNA using BCSP31 target gene and IS711 locus. The PCR assay showed that an amplicon of 223 bp was obtained in 73.8% (133/180) of the tested sera using primers (B4/B5) derived from a gene encoding the 31-kDa Brucella abortus antigen. In another PCR, an amplicon of 498 bp was obtained in 63.8% (115/180) of the samples using Brucella abortus-specific primers derived from a locus adjacent to the 3'-end of IS711, and also an amplicon of 731 bp was produced in 4.4% (8/180) of the tested samples using Brucella melitensis-specific primers. When the Wright method was used as a gold standard, the sensitivity and specificity of the PCR technique for genus identification were found to be 96 and 80.7%, respectively. However, the sensitivity value obtained with the species-specific PCR method was 82%, and specificity was similar to that previous reported. This is the first report of a high frequency of Brucella abortus in patients suspicious of Brucellosis from the Zanjan province.
Abstract in English:Staphylococcus epidermidis which exists in healthy human skin as a commensal inhabitant is also an important pathogen forming biofilms on many surfaces and recently, increased resistance traits were suggested to be acquired in biofilm environments. In this study; clinical Prevalences, antibiotic resistances and biofilm formations of S. epidermidis strains were determined and comparison of all these findings with each other was carried out in order to take precautions against them and figure out if high biofilm forming S. epidermidis strains display multi drug resistance. According to our results; samples of wound and blood were the most S. epidermidis isolated clinical materials (40%; 35%) and cardiothoracic surgery was the most S. epidermidis observed service unit. All of these strains were sensitive to vancomycin, however 65% of them showed resistance to all β-lactam antibiotics (Penicillin, Oxacillin, Amoxicilin / Clavulonic acid), used in this study and 60% of all S. epidermidis strains were found as multi drug resistant. When the results of strong biofilm forming S. epidermidis strains are examined; they were isolated from sample of blood and service unit of cardiovascular surgery in highest frequency and 80% of them were β-lactam resistant whereas 100% of them were multi drug resistant. One of these multi drug resistant strains which was resistant to maximum amount of different antimicrobial classes, was also observed as maximum biofilm forming strain among all the other S. epidermidis isolates. Multi drug resistance in strong biofilm forming strains shows that; biofilms play a role in antimicrobial resistance traits of S. epidermidis.
Abstract in English:Fungal infections have become a major problem of worldwide concern. Yeasts belonging to the Candida genus and the pathogenic fungus Cryptococcus neoformans are responsible for different clinical manifestations, especially in immunocompromised patients. Antifungal therapies are currently based on a few chemotherapeutic agents that have problems related to effectiveness and resistance profiles. Microemulsions are isotropic, thermodynamically stable transparent systems of oil, water and surfactant that can improve the solubilization of lipophilic drugs. Taking into account the need for more effective and less toxic drugs along with the potential of thiophene derivatives as inhibitors of pathogenic fungi growth, this study aimed to evaluate the antifungal activity of a thiophene derivative (5CN05) embedded in a microemulsion (ME). The minimum inhibitory concentration (MIC) was determined using the microdilution method using amphotericin B as a control. The formulations tested (ME- blank and ME-5CN05) showed physico-chemical properties that would allow their use by the topical route. 5CN05 as such exhibited moderate or weak antifungal activity against Candida species (MIC = 270-540 µg.mL-1) and good activity against C. neoformans (MIC = 17 µg.mL-1). Candida species were susceptible to ME-5CN05 (70-140 µg.mL-1), but C. neoformans was much more, presenting a MIC value of 2.2 µg.mL-1. The results of this work proved promising for the pharmaceutical industry, because they suggest an alternative therapy against C. neoformans.
Abstract in English:The entomopathogenic fungus Beauveria bassiana (Balsamo 1835) Vuillemin is an effective alternative control agent against some agricultural pests and biological vectors of important diseases such as Chagas disease. In this work we studied an isolate of Beauveria bassiana from of the town of San Antonio Rayón, Puebla, Mexico and its entomopathogenic effects on Meccus pallidipennis (Stal 1872). Phylogenetic analysis using molecular comparison of the ITS and EF1α genes, showed that the resulting cladogram places the BUAP 04 strain with a relationship closer to the AFAO 9-6 strain, within the diversity of the B. bassiana sensu lato group. Although there was the possibility that BUAP 04 strain was a direct descendant of strains used in campaigns of biologic control, molecular study allowed us to recognize that it was a different fungus due to numerous inserts. A strain isolated from a T. dimiata was evaluated for pathogenicity against another triatoma (Meccus pallidipennis) species obtaining an LC50 of 4.16 x 10(6) spores/mL, confirming that the BUAP 04 strain is virulent for M. pallidipennis and could be a good prospect for formulations to control M. pallidipennis.
Abstract in English:Ochrobactrum anthropi infection in newborn patients is rare, and the treatment is challenging because of its widespread and unpredictable resistance to antimicrobial agents and discrepancies between in vitro susceptibility and in vivo efficacy. We report the clinical and microbiological characteristics of Ochrobactrum anthropi bacteremia in a preterm patient.
Abstract in English:Halophilic bacteria are commonly found in natural environments containing significant concentration of NaCl such as inland salt lakes and evaporated sea-shore pools, as well as environments such as curing brines, salted food products and saline soils. Dependence on salt is an important phenotypic characteristic of halophilic bacteria, which can be used in the polyphasic characterization of newly discovered microorganisms. In this study the diversity of halophilic bacteria in foreshore soils of Daecheon, Chungnam, and Saemangeum, Jeonbuk, was investigated. Two types of media, namely NA and R2A supplemented with 3%, 5%, 9%, 15%, 20% and 30% NaCl were used. More than 200 halophilic bacteria were isolated and BOX-PCR fingerprinting analysis was done for the typing of the isolates. The BLAST identification results showed that isolated strains were composed of 4 phyla, Firmicutes (60%), Proteobacteria (31%), Bacteriodetes (5%) and Actinobacteria (4%). Isolates were affiliated with 16 genera and 36 species. Bacillus was the dominant genus in the phylum Firmicutes, comprising 24% of the total isolates. Halomonas (12%) and Shewanella (12%) were also found as the main genera. These findings show that the foreshore soil of Daecheon Beach and Saemangeum Sea of Korea represents an untapped source of bacterial biodiversity.
Abstract in English:Chromium pollution is produced in connection with industrial processes like in tanneries. It has been suggested that bioremediation could be a good option for clean up. The stress effect of variable chromate levels, pHs and growth temperatures on biochemical parameters of two Cr(VI) reducing bacterial strains Pseudomonas aeruginosa Rb-1 and Ochrobactrum intermedium Rb-2 was investigated. Transmission electrone microscopy (TEM) was performed to study the intracellular distribution of Cr(VI). It was observed that initial stress of 1000 µgmL-1 caused significant enhancement of all studied biochemical parameters at pH 7.0 and growth temperature of 37 °C showing great bioremediation potential of the strains. Transmission electron microscopy revealed that the distribution of chromium precipitates was not uniform as they were distributed in the cytoplasm as well as found associated with the periplasm and outer membrane. Fourier transform infrared spectroscopy showed the possible involvement of carboxyl, amino, sulpohonate and hydroxyl groups present on the bacterial cell surface for the binding of Cr(VI) ions. Cr(VI) stress brought about changes in the distridution of these functional groups. It can be concluded that the investigated bacterial strains adjust well to Cr(VI) stress in terms of biochemical parameters and along that exhibited alteration in morphology.
Abstract in English:Arbuscular mycorrhizal fungi (AMF) colonize land plants in every ecosystem, even extreme conditions such as saline soils. In the present work we report for the first time the mycorrhizal status and the vertical fungal distribution of AMF spores present in the rhizospheric soil samples of four species of Chenopodiaceae (Allenrolfea patagonica, Atriplex argentina, Heterostachys ritteriana and Suaeda divaricata) at five different depths in two saline of central Argentina. Roots showed medium, low or no colonization (0-50%). Nineteen morphologically distinctive AMF species were recovered. The number of AMF spores ranged between 3 and 1162 per 100 g dry soil, and AMF spore number decreased as depth increased at both sites. The highest spore number was recorded in the upper soil depth (0-10 cm) and in S. divaricata. Depending of the host plant, some AMF species sporulated mainly in the deep soil layers (Glomus magnicaule in Allenrolfea patagonica, Septoglomus aff. constrictum in Atriplex argentina), others mainly in the top layers (G. brohultti in Atriplex argentina and Septoglomus aff. constrictum in Allenrolfea patagonica). Although the low percentages of colonization or lack of it, our results show a moderate diversity of AMF associated to the species of Chenopodiaceae investigated in this study. The taxonomical diversity reveals that AMF are adapted to extreme environmental conditions from saline soils of central Argentina.
Abstract in English:A transconjugant of Azotobacter chroococcum Mac 27 tagged with lac Z(A. chroococcum Mac27 L) was found to possess high levels of β-galactosidase activity constitutively.Further, the lac Z marker was found to be stably integrated into the chromosome of the A. chroococcum Mac 27 and did not have any adverse effect on growth, nitrogen fixation and excretion of ammonia. A quick method to determine the viable cell number in broth culture and carrier based inoculants has been developed on the basis of β-galactosidase assay. It was found that there was a direct relationship between the number of cell as determined by standard plate count and intensity of colour that developed upon degradation of ONPG due to β-galactosidase activity .The method was found to be sensitive enough to determine 1.7 x 10(6) CFU mL-1 in broth culture as well as carrier based Azotobacter inoculants. Further, it was observed that when A. chroococcum Mac27 L was inoculated on Brassica campestris, it could be detected in the presence of other bacteria capable of growing on Burks agar medium containing X-gal on the basis of lac Z genetic marker.
Abstract in English:Glucose dehydrogenase (GDH; EC 1.1. 5.2) is the member of quinoproteins group that use the redox cofactor pyrroloquinoline quinoine, calcium ions and glucose as substrate for its activity. In present study, Leclercia sp. QAU-66, isolated from rhizosphere of Vigna mungo, was characterized for phosphate solubilization and the role of GDH in plant growth promotion of Phaseolus vulgaris. The strain QAU-66 had ability to solubilize phosphorus and significantly (p < 0.05) promoted the shoot and root lengths of Phaseolus vulgaris. The structural determination of GDH protein was carried out using bioinformatics tools like Pfam, InterProScan, I-TASSER and COFACTOR. These tools predicted the structural based functional homology of pyrroloquinoline quinone domains in GDH. GDH of Leclercia sp. QAU-66 is one of the main factor that involved in plant growth promotion and provides a solid background for further research in plant growth promoting activities.
Abstract in English:Less than 0.5% of total water in the world is available for human consumption and agriculture. The major part of the world's water is saline and salinity in soils interferes in germination of seeds and the posterior development of the plant. In order to increase the osmotolerance of tomato, seedlings were associated with Azospirillum brasilense Cd, Azospirillum brasilense Cd transformed bacteria with a plasmid harboring a trehalose biosynthesis gene-fusion or Chlorella vulgaris. Two plant culture media: Hydroponic and Murashige and Skoog were tested. In the first set of studies seedlings were associated to single free cells meanwhile in a second set single and combined free cells were studied. A positive interaction between transformed Azospirillum and Chlorella vulagris and tomato plants was observed. Seedlings showed a salt concentration tolerance, as sodium chloride, up to 200 mM. According to our results, the association of plants with A. brasilense Cd-BIF and C. vulgaris is a viable approach to increase their salt tolerance and biomass, as consequence the possible use of sea water to irrigate horticultural plants.
Abstract in English:Eight endophytic isolates assigned to Pseudomonas, Azospirillum, and Bacillus genera according to pheno-genotypic features were retrieved from barley seeds under selective pressure for nitrogen-fixers. Genetic relationships among related isolates were investigated through RAPD. Six isolates displayed nitrogen-fixing ability, while all could biosynthesize indolacetic acid in vitro and showed no antibiosis effects against Azospirillum brasilense Az39, a recognized PGPR.
Abstract in English:Biofilm formation depends on several factors. The influence of different osmolarities on bacterial biofilm formation was studied. Two strains (Enterobacter sp. and Stenotrophomonas sp.) exhibited the most remarkable alterations. Biofilm formation is an important trait and its use has been associated to the protection of organisms against environmental stresses.
Abstract in English:Post-mortem bacterial culture and specific biochemical tests are currently performed to characterize the etiologic agent of bovine tuberculosis. Cultures take up to 90 days to develop. A diagnosis by molecular tests such as PCR can provide fast and reliable results while significantly decreasing the time of confirmation. In the present study, a nested-PCR system, targeting rv2807, with conventional PCR followed by real-time PCR, was developed to detect Mycobacterium tuberculosis complex (MTC) organisms directly from bovine and bubaline tissue homogenates. The sensitivity and specificity of the reactions were assessed with DNA samples extracted from tuberculous and non-tuberculous mycobacteria, as well as other Actinomycetales species and DNA samples extracted directly from bovine and bubaline tissue homogenates. Regarding the analytical sensitivity, DNA of the M. bovis AN5 strain was detected up to 1.5 pg by nested-PCR, whereas DNA of M. tuberculosis H37Rv strain was detected up to 6.1 pg. The nested-PCR system showed 100% analytical specificity for MTC when tested with DNA of reference strains of non-tuberculous mycobacteria and closely-related Actinomycetales. A clinical sensitivity level of 76.7% was detected with tissues samples positive for MTC by means of the culture and conventional PCR. A clinical specificity of 100% was detected with DNA from tissue samples of cattle with negative results in the comparative intradermal tuberculin test. These cattle exhibited no visible lesions and were negative in the culture for MTC. The use of the nested-PCR assay to detect M. tuberculosis complex in tissue homogenates provided a rapid diagnosis of bovine and bubaline tuberculosis.
Abstract in English:Ehrlichiosis is a worldwide distributed disease caused by different bacteria of the Ehrlichia genus that are transmitted by arthropod vectors. Its occurrence in dogs is considered endemic in several regions of Brazil. Regarding cats, however, few studies have been done and, consequently, there is not enough data available. In order to detect Ehrlichia spp. in cats from the central-western region of Brazil, blood and serum samples were collected from a regional population of 212 individuals originated from the cities of Cuiabá and Várzea Grande. These animals were tested by the Immunofluorescence Assay (IFA) and the Polymerase Chain Reaction (PCR) designed to amplify a 409 bp fragment of the dsb gene. The results obtained show that 88 (41.5%) cats were seropositive by IFA and 20 (9.4%) cats were positive by PCR. The partial DNA sequence obtained from PCR products yielded twenty samples that were found to match perfectly the Ehrlichia canis sequences deposited on GenBank. The natural transmission of Ehrlichia in cats has not been fully established. Furthermore, tick infestation was not observed in the evaluated cats and was not observed any association between age, gender and positivity of cats in both tests. The present study reports the first serological and molecular detection of E. canis in domestic cats located in the endemic area previously mentioned.
Abstract in English:Bacteroides fragilis colonizes dog guts both as a commensal and as an opportunistic pathogen. This study aims to evaluate virulence factors of 13 B. fragilis strains isolated from dog intestinal tracts and their ability for biofilm formation. Capsules were detected in all the evaluated strains. A total of 61.5% of all strains were biofilm producers. These attributes most likely play an important role in B. fragilis persistent colonization in the gut.
Abstract in English:Oxacillin/methicillin-resistance is related to the mecA and its regulatory genes mecR1 and mecI. Its origin is still unknown, although evidences support that it is related to CNS, once mecA and a homologue gene, pbpD, were both detected in Staphylococcus sciuri species group. The present work evaluated 210 samples of skin and ear swabs from rodents and 60 nasal swabs from equines of Army Biologic Institute, Rio de Janeiro. Pheno- and genotypic characterization provided 59.52% (25/42) and 78.57% (11/14) S. lentus and S. sciuri, respectively. It was observed that although all S. sciuri isolates tested positive for pbpD, there was no correlation with oxacillin-resistance. On the other hand, isolates tested positive for mecA gene also presented phenotypic oxacillin-resistance in at least one assay. The alignment of the mecA gene showed that the nucleotide sequences were sorted into 2 different groups, one comprising the bovine strains and the other containing human and equine strains.
Abstract in English:Bovine tuberculosis is a major infectious disease of the cattle. In this study, 85 M. bovis isolates from 162 lymph nodes, obtained from a herd of cattle on a farm in southern Brazil, were evaluated using spoligotyping and VNTR. The strains were grouped into five clusters and five orphans, showing a heterogenic genetic profile, what could represent diverse geographic origins of the introduced cows and/or the frequent movement of cattle between different properties.
Abstract in English:The req_39680 gene, associated to a putative efflux system, was detected in 60% (54/90) of R. equi isolates by PCR. The phenotypic expression of efflux mechanism was verified in 20% of the isolates using ethidium bromide. For the first time, the expression of efflux mechanism was demonstrated in R. equi.
Abstract in English:Salmonella enterica and Shigella species are commonly associated with food and water borne infections leading to gastrointestinal diseases. The present work was undertaken to develop a sensitive and reliable PCR based detection system for simultaneous detection of Salmonella enterica and Shigella at species level. For this the conserved regions of specific genes namely ipaH1, ipaH, wbgZ, wzy and invA were targeted for detection of Shigella genus, S. flexneri, S. sonnei, S. boydii and Salmonella enterica respectively along with an internal amplification control (IAC). The results showed that twenty Salmonella and eleven Shigella spp., were accurately identified by the assay without showing non-specificity against closely related other Enterobacteriaceae organisms and also against other pathogens. Further evaluation of multiplex PCR was undertaken on 50 natural samples of chicken, eggs and poultry litter and results compared with conventional culture isolation and identification procedure. The multiplex PCR identified the presence of Salmonella and Shigella strains with a short pre-enrichment step of 5 h in peptone water and the same samples were processed by conventional procedures for comparison. Therefore, this reported multiplex PCR can serve as an alternative to the tedious time-consuming procedure of culture and identification in food safety laboratories.
Abstract in English:A mesophilic Enterobacter sp. Bn12 producing an alkaline thermostable lipase was isolated from soil in Tehran, Iran. The lipase gene (ELBn12) was identified from a genomic library. Sequence analysis of the DNA fragment revealed an open reading frame of 879 bp encoding a lipase with a molecular mass of 31.3 kDa. The deduced amino acid sequence showed 96% identity with a lipase of Enterobacter sp. Ag1 and the identity of their DNA sequences was 88.9%. ELBn12 belongs to the lipase subfamily I.1 and its catalytic triad consists of Ser82, Asp237 and His259. The lipase was expressed in Escherichia coli (BL21) pLysS and partially purified by anion exchange chromatography. The maximum activity of ELBn12 was obtained at temperature of 60 °C and pH 8.0 towards tricaprylin (C8) and its specific activity was around 2900 U/mg. ELBn12 was stable within a broad pH range from 6.0 to 11.0. The enzyme showed high stability in both polar and nonpolar organic solvents at 50% (v/v). The lipase activity was enhanced in the presence of 10 mM of Ca2+, Mg2+ and K+, while heavy metals (Fe3+ and Zn2+) had strong inhibitory effect. ELBn12 showed high activity in the presence of 1% (w/v) nonionic surfactants, however ionic surfactants inhibited the lipolytic activity. ELBn12 characteristics show that it has a potential to be used in various industrial processes.
Abstract in English:Oncogenic HPV genotypes are strongly associated with premalignant and malignant cervical lesion. The purpose was to determine human papillomavirus (HPV) prevalence and genotypes, and to estimate cervical cancer risk factor associations. Cervical samples were obtained from 251 women seeking gynecological care at the Pelotas School of Medicine Clinic. This is a cross-sectional study. HPV-DNA was amplified by nested-PCR using MY09/11 and GP5/6 primers, and the sequencing was used for genotyping. Sociodemographic and behavioral risk factors were obtained by closed questionnaire, and its relationship to HPV infection prevalence were analyzed. Statistical analyses were performed using SPSS 16.0 software, and differences were considered significant at p < 0.05. As results, the prevalence of HPV infection was 29.9%. The most frequent genotype was HPV-16 (41.3%), followed by HPV-18 (17.3%), and HPV-33 (9.3%). Others nine HPV genotypes were also found. On this population, prevalence of oncogenic HPV genotypes was high, but does not seem to confer relationship with the risk factors investigated. Future investigations in larger populations are necessary, for the proposition of more appropriated monitoring strategies and treatment according to the Brazilian health service reality, as well as patients.
Abstract in English:Leishmania RNA Virus (LRV, Totiviridae) infect Leishmania cells and subvert mice immune response, probably promoting parasite persistence, suggesting significant roles for LRV in host-parasite interaction. Here we describe a new LRV1-4 purification protocol, enabling capsid visualization by negatively stained electron microscopy representing a significant contribution to future LRV investigations.
Abstract in English:The objective of this study was to evaluate the antimicrobial potential of Lippia alba essential oil (EOLa) and to investigate the effect of food ingredients on its efficacy. The antimicrobial potential of the oil was determined by the presence or absence of inhibition zones, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Escherichia coli, Listeria innocua, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella choleraesuis and Staphylococcus aureus. The effect of food ingredients and the pH on the antimicrobial efficacy of oil was assessed by monitoring the maximum growth rate of Listeria monocytogenes in model media. The model media included potato starch (0, 1, 5 or 10%), beef extract (1, 5, 3, 6 or 12%), sunflower oil (0, 5 or 10%) and TSB broth at pH levels of 4, 5, 6 or 7. The EOLa showed efficacy at all concentrations (50%, 25%, 6.25%, 3%, 1.5%, 0.8%, 0.4% and 0.2%) evaluated, against all bacterial species, Gram-positive and Gram-negative. The antimicrobial efficacy of EO was found to be a function of ingredient manipulation. Proteins and lipids had a negative impact on the oil effectiveness, indicating the protective action of both on the microbial specie tested. On the contrary, at the highest concentration of starch (10%), the lower rate growth of L. monocytogenes was detected, therefore indicating a positive effect of carbohydrates on the oil effectivenes. Regarding the pH, the studies showed that the rate of microbial growth increased with increasing pH. It was concluded that the use of EOLa is more effective control pathogenic and spoilage bacteria when applied to starchy foods under an acidic pH.
Abstract in English:Milk is widely consumed in Brazil and can be the vehicle of agent transmission. In this study, was evaluated the occurrence of Mycobacterium bovis and non-tuberculous mycobacteria (NTM) in raw and pasteurized milk consumed in the northwestern region of Paraná, Brazil. Fifty-two milk samples (20 pasteurized and 32 raw) from dairy farms near the municipality of Maringa, Parana State, Brazil were collected. Milk samples were decontaminated using 5% oxalic acid method and cultured on Lowenstein-Jensen and Stonebrink media at 35 °C and 30 °C, with and without 5-10% CO2. Mycobacteria isolates were identified by morphological features, PCR-Restriction Fragment Length Polymorphism Analysis (PCR-PRA) and Mycolic acids analysis. Thirteen (25%) raw and 2 (4%) pasteurized milk samples were positive for acid fast bacilli growth. Nine different species of NTM were isolated (M. nonchromogenicum, M. peregrinum, M. smegmatis, M. neoaurum, M. fortuitum, M. chelonae, M. flavescens, M. kansasii and M. scrofulaceum). M. bovis was not detected. Raw and pasteurized milk may be considered one source for NTM human infection. The paper reinforces the need for intensification of measures in order to avoid the milk contamination and consequently prevent diseases in the south of Brazil.
Abstract in English:The artisanal Minas cheese is produced from raw cow's milk and wooden utensils were employed in its manufacture, which were replaced by other materials at the request of local laws. This substitution caused changes in the traditional characteristics of cheese. Due to the absence of scientific studies indicating the microbial composition of biofilms formed on wooden forms, tables and shelves used in these cheese production, the present work evaluated the counts of Staphylococcus aureus, Escherichia coli, coliforms at 32 °C, yeasts, presumptive mesophilic Lactobacillus spp. and Lactococcus spp. in these biofilms, milk, whey endogenous culture and ripened cheese in two traditional regions: Serro and Serra da Canastra. Also, we checked for the presence of Salmonella sp. and Listeria monocytogenes in the ripened cheeses. The ultra structure of the biofilms was also assessed. Counts above legislation (> 2 log cfu/mL) for the pathogens evaluated were found in milk samples from both regions. Only one shelf and one form from Serro were above limits proposed (5 cfu/cm² for S. aureus and E. coli and 25 cfu/cm² for coliforms) in this study for contaminants evaluated. In Canastra, few utensils presented safe counting of pathogens. There was no Salmonella sp. and Listeria monocytogenes in the cheeses after ripening. Thus, the quality of the cheese is related to improving the microbiological quality of milk, implementation and maintenance of good manufacturing practices, correct cleaning of wooden utensils, and not its replacement.
Abstract in English:DNJ, an inhibitor of α-glucosidase, is used to suppress the elevation of postprandial hyperglycemia. In this study, we focus on screening an appropriate microorganism for performing fermentation to improve DNJ content in mulberry leaf. Results showed that Ganoderma lucidum was selected from 8 species and shown to be the most effective in improvement of DNJ production from mulberry leaves through fermentation. Based on single factor and three factor influence level tests by following the Plackett-Burman design, the optimum extraction yield was analyzed by response surface methodology (RSM). The extracted DNJ was determined by reverse-phase high performance liquid chromatograph equipped with fluorescence detector (HPLC-FD). The results of RSM showed that the optimal condition for mulberry fermentation was defined as pH 6.97, potassium nitrate content 0.81% and inoculums volume 2 mL. The extraction efficiency reached to 0.548% in maximum which is 2.74 fold of those in mulberry leaf.
Abstract in English:Safety issues related to the employment of synthetic colorants in different industrial segments have increased the interest in the production of colorants from natural sources, such as microorganisms. Improved cultivation technologies have allowed the use of microorganisms as an alternative source of natural colorants. The objective of this work was to evaluate the influence of some factors on natural colorants production by a recently isolated from Amazon Forest, Penicillium purpurogenum DPUA 1275 employing statistical tools. To this purpose the following variables: orbital stirring speed, pH, temperature, sucrose and yeast extract concentrations and incubation time were studied through two fractional factorial, one full factorial and a central composite factorial designs. The regression analysis pointed out that sucrose and yeast extract concentrations were the variables that influenced more in colorants production. Under the best conditions (yeast extract concentration around 10 g/L and sucrose concentration of 50 g/L) an increase of 10, 33 and 23% respectively to yellow, orange and red colorants absorbance was achieved. These results show that P. purpurogenum is an alternative colorants producer and the production of these biocompounds can be improved employing statistical tool.
Abstract in English:The use of low cost agro-industrial residues for the production of industrial enzymes is one of the ways to reduce significantly production costs. Cellulase producing actinomycetes were isolated from soil and decayed agricultural wastes. Among them, a potential culture, strain NEAE-J, was selected and identified on the basis of morphological, cultural, physiological and chemotaxonomic properties, together with 16S rDNA sequence. It is proposed that strain NEAE-J should be included in the species Streptomyces albogriseolus as a representative of a novel sub-species, Streptomyces albogriseolus subsp. cellulolyticus strain NEAE-J and sequencing product was deposited in the GenBank database under accession number JN229412. This organism was tested for its ability to produce endoglucanase and release reducing sugars from agro-industrial residues as substrates. Sugarcane bagasse was the most suitable substrate for endoglucanase production. Effects of process variables, namely incubation time, temperature, initial pH and nitrogen source on production of endoglucanase by submerged fermentation using Streptomyces albogriseolus subsp. cellulolyticus have been studied. Accordingly optimum conditions have been determined. Incubation temperature of 30 ºC after 6 days, pH of 6.5, 1% sugarcane bagasse as carbon source and peptone as nitrogen source were found to be the optimum for endoglucanase production. Optimization of the process parameters resulted in about 2.6 fold increase in the endoglucanase activity. Therefore, Streptomyces albogriseolus subsp. cellulolyticus coud be potential microorganism for the intended application.