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Brazilian Journal of Chemical Engineering, Volume: 22, Número: 4, Publicado: 2005
  • Indirect estimation of Bacillus thuringiensis var. israelensis biomass concentration using oxygen balance data Biotechnology

    Silveira, M. M.; Molina, M. A. B.

    Resumo em Inglês:

    The kinetic analysis of Bacillus thuringiensis var. israelensis (Bti) growth is often hindered by the impossibility of using conventional methods to measure biomass concentration in natural raw-material-based media, which normally have a high content of insoluble solids. In this work, application of a mathematical model based on respiratory parameters in the estimation of Bti biomass concentration was evaluated. The values obtained for the respiratory parameters true cell yield from oxygen consumption and maintenance coefficient for oxygen (mO) were 0.091 g cell/mmol O2 and 2.1 mmol O2/g cell/hour, respectively. With these constants and the oxygen uptake rates obtained from oxygen balance calculations, cell concentrations of Bti were estimated in batch runs with initial glucose concentrations from 10 to 80 g/L and were found to be in good agreement with experimental data.
  • Concentration of alpha-lactalbumin from cow milk whey through expanded bed adsorption using a hydrophobic resin Biotechnology

    Conrado, L. S.; Veredas, V.; Nóbrega, E. S.; Santana, C. C.

    Resumo em Inglês:

    The design of novel applications for the use of new high-density adsorbents in the direct recovery of proteins requires analysis of the fluid dynamics and mass transfer characteristics of the column used with the solid-liquid system. In this article we describe the operating parameters related to the use of a high-density, hydrophobic resin (Streamline® Phenyl) for the recovery of alpha-lactalbumin from cow milk whey in an expanded-bed adsorption mode of operation. The adsorption isotherm, kinetic curves and chromatographic curves for adsorption and elution were determined for alpha-lactalbumin recovered from whole whey. The experiments were used to confirm the theoretical model that involves the combination of resistance to the mass transfer in the liquid phase and diffusivity in the adsorbent resin pores. The model solution was obtained through the orthogonal collocation method. A nonlinear multivariable optimization method was used to fit the model to experimental results. A purity of 79% was obtained with the adsorption/elution protocol prior to any polishing procedure.
  • Development and evaluation of a radial anaerobic/aerobic reactor treating organic matter and nitrogen in sewage Biotechnology

    Garbossa, L. H. P.; Lapa, K. R.; Zaiat, M.; Foresti, E.

    Resumo em Inglês:

    The design and performance of a radial anaerobic/aerobic immobilized biomass (RAAIB) reactor operating to remove organic matter, solids and nitrogen from sewage are discussed. The bench-scale RAAIB was divided into five concentric chambers. The second and fourth chambers were packed with polyurethane foam matrices. The performance of the reactor in removing organic matter and producing nitrified effluent was good, and its configuration favored the transfer of oxygen to the liquid mass due to its characteristics and the fixed polyurethane foam bed arrangement in concentric chambers. Partial denitrification of the liquid also took place in the RAAIB. The reactor achieved an organic matter removal efficiency of 84%, expressed as chemical oxygen demand (COD), and a total Kjeldahl nitrogen (TKN) removal efficiency of 96%. Average COD, nitrite and nitrate values for the final effluent were 54 mg.L-1, 0.3 mg.L-1 and 22.1 mg.L-1, respectively.
  • A fuzzy logic algorithm for identification of the harvesting threshold during PGA production by Bacillus megaterium Biotechnology

    Nucci, E. R.; Silva, R. G.; Gomes, T. C.; Giordano, R. C.; Cruz, A. J. G.

    Resumo em Inglês:

    Penicillin G acylase (PGA) is an important enzyme used as biocatalyst in the production of semisynthetic beta-lactam antibiotics. Many microorganisms produce this enzyme and recombinant Escherichia coli has been preferred use for industrial applications. Bacillus megaterium is one of the microorganisms that excretes this enzyme into the medium. As a consequence, separation and purification steps are simplified. On-line measurement of enzyme activity during cultivation using in-situ sensors is a difficult task in the industrial environment due to the lack of robust and inexpensive instrumentation. This work presents the results of a fuzzy logic algorithm used to determine the moment of maximum enzyme concentration during Bacillus megaterium cultivations in an aerated and stirred, automated lab-scale bioreactor. The fuzzy algorithm was written in Fortran, compiled as a dynamic link library and implemented on a platform developed in MS-Visual Basic. Data were exchanged in real time between the platform and the supervisory system, which was coupled to the bioreactor. It was possible to determine the moment at which maximum enzyme activity was reached in several bioreactor assays. At this point, the end of the process was indicated to the operator. The results illustrate the importance of using reliable computational intelligence-based algorithms in biochemical reactions.
  • Stabilization of penicillin G acylase by immobilization on glutaraldehyde-activated chitosan Biotechnology

    Adriano, W. S.; Filho, E. H. C.; Silva, J. A.; Giordano, R. L. C.; Gonçalves, L. R.B.

    Resumo em Inglês:

    The objective of this work was to study enzyme immobilization on chitosan activated with glutaraldehyde, aiming to produce a cheap biocatalyst. Two different immobilization strategies were studied: one-point and multipoint covalent attachment to the solid matrix. The multipoint covalent attachment derivative had an 82% immobilization yield. It was 4.9-fold more stable than the free enzyme at 50°C and 4.5-fold more stable than soluble enzyme at pH 10.0. The one-point derivative had an 85% immobilization yield. It was 2.7-fold more stable than the free enzyme at 50°C and 3.8-fold more stable than soluble PGA at pH 10.0. Results indicated that chitosan can be loaded with PGA above 330 IU/g. Intraparticle diffusive effects, however, limited hydrolysis of penicillin G catalyzed by those derivatives at 37°C and 25°C. Operational stability assays were performed and the multipoint derivative exhibited a half-life of 40 hours.
  • Adsorption of the inulinase from Kluyveromyces marxianus NRRL Y-7571 on Streamline® DEAE resin Biotechnology

    Makino, Y.; Lima, P. S. C.; Filho, F. M.; Rodrigues, M. I.

    Resumo em Inglês:

    The enzyme inulinase is used to produce oligosaccharides and fructose, with up to 95% fructose in a single stage of inulina hydrolysis. With in the aim to purify the enzyme, studies on the conditions of enzyme adsorption in an expanded-bed column were conducted using phosphate and tris-HCl buffers. The inulinase used in this work was obtained from Kluyveromyces marxianus NRRL Y-7571 by fermentation in an industrial medium. Using the anionic resin Streamline DEAE, the adsorption equilibrium time was determined. It was observed that the adsorption isotherm follows the Langmuir model; the parameters for the maximum amount of adsorbed inulinase (Qm) and the dissociation constant (k d) were determined. With 0.05 M sodium phosphate buffer at pH 6.0, the parameter values 1428 UI/mL and 2 UI/mL with a correlation coefficient of 0.96 were obtained. For 0.02 M tris-HCl buffer at pH 7.5, the same parameters were 5000 UI/mL and 0.05 UI/mL with a correlation coefficient of 0.99. The best purification conditions for the fixed bed were shown to be a 0.4 M phosphate buffer with NaCl as eluter, a purification factor of 11.4, and a recovery yield of up to 79%.
  • Citric acid production by solid-state fermentation on a semi-pilot scale using different percentages of treated cassava bagasse Biotechnology

    Prado, F. C.; Vandenberghe, L. P. S.; Woiciechowski, A. L.; Rodrígues-León, J. A.; Soccol, C. R.

    Resumo em Inglês:

    Citric acid is commercailly important product used in several industrial processes. Solid-state fermentation (SSF) has become an alternative method for citric acid production using agro-industrial residues such as cassava bagasse (CB). Use of CB as substrate can avoid the environmental problems caused by its disposal in the environment. The aim of this work was to verify the effect of different percentages of gelatinized starch in CB on production of citric acid by SSF in horizontal drum and tray-type bioreactors. Gelatinization was used in order to make the starch structure more susceptible to consumption by the fungus. The best results (26.9 g/100g of dry CB) were obtained in horizontal drum bioreactor using 100% gelatinized CB, although the tray-type bioreactor offers advantages and shows promise for large-scale citric acid production in terms of processing costs.
  • A study on clavulanic acid production by Streptomyces clavuligerus in batch, fed-batch and continuous processes Biotechnology

    Neto, A. B.; Hirata, D. B.; Cassiano Filho, L. C. M.; Bellão, C.; Badino Júnior, A. C.; Hokka, C. O.

    Resumo em Inglês:

    Clavulanic acid (CA) is a potent inhibitor of beta-lactamases, enzymes that are responsible for the hydrolysis of beta-lactam antibiotics. It is a secondary metabolite produced by the filamentous aerobic bacterium Streptomyces clavuligerus in submerged cultivations. In the present work clavulanic acid production in batch, fed-batch and continuous bioreactors was studied with the objective of increasing productivity. The operating conditions: temperature, aeration and agitation, were the same in all cases, 28º C, 0.5 vvm and 800 rpm, respectively. The CA concentration obtained in the fed-batch culture, 404 mg L-1, was ca twice the value obtained in the batch culture, 194 mg L-1, while 293 mg L-1 was obtained in the continuous culture. The highest productivity was obtained in the continuous cultivation, 10.6 mg L-1 h-1, as compared with 8.8 mg L-1 h-1 in the fed-batch process and 3.5 mg L-1 h-1 in the batch process, suggesting that continuous culture of Streptomyces clavuligerus is a promising strategy for clavulanic acid production.
  • The bioactivation procedure for increasing the sulphate-reducing bacteria in a UASB reactor Biotechnology

    Gonçalves, M. M. M.; Leite, S. G. F.; Sant'Anna Jr, G. L.

    Resumo em Inglês:

    Bioactivation, a procedure to obtain anaerobic sulphidogenic sludge, was developed in order to increase sulphate reduction and, consequently, sulphide production to remove metals from effluents. This procedure, in which the source of carbon/energy (lactate) is gradually replaced, consisted of three operational conditions. It was observed that bioactivation took six months so there was a 100-fold increase in the population of sulphate-reducing bacteria estimated by the most-probable-number (MPN) when molasses was employed as a new source.
  • Application of the wavelet image analysis technique to monitor cell concentration in bioprocesses Biotechnology

    Garófano, G. J. R.; Venancio, C. G.; Suazo, C. A. T.; Almeida, P. I. F.

    Resumo em Inglês:

    The growth of cells of great practical interest, such as, the filamentous cells of bacterium Streptomyces clavuligerus, the yeast Saccharomyces cerevisiae and the insect Spodoptera frugiperda (Sf9) cell, cultivated in shaking flasks with complex media at appropriate temperatures and pHs, was quantified by the new wavelet transform technique. This image analysis tool was implemented using Matlab 5.2 software to process digital images acquired of samples taken of these three types of cells throughoot their cultivation. The values of the average wavelet coefficients (AWCs) of simplified images were compared with experimental measurements of cell concentration and with computer-based densitometric measurements. AWCs were shown to be directly proportional to measurements of cell concentration and to densitometric measurements, making evident the great potential of the wavelet transform technique to quantitatively estimate the growth of several types of cells.
  • Mathematical modeling of capsular polysaccharide production by Neisseria meningitidis serogroup C in bioreactors Biotechnology

    Henriques, A. W. S.; Jessouroun, E.; Lima, E. L.; Alves, T. L. M.

    Resumo em Inglês:

    In this work, the process of capsular polysaccharide production by Neisseria meningitidis serogroup C was studied. Batch experimental runs were conducted in a set of one-liter bioreactors with 0.5 L of Frantz cultivation medium. Cultivation temperature and pH were controlled at optimal pre-established values. The dynamic behavior of the bacteria was analyzed based on biomass growth, glucose uptake, polysaccharide production and dissolved oxygen time profile obtained in a set of experimental runs with initial concentrations of glucose that varied from 5 to 13.5 g/L. Formulated hypotheses were then employed in the construction of a phenomenological model of the bioprocess under study that successfully described the dynamic behavior of the system and can be used in future control and optimization of the industrial process of capsular polysaccharide production.
  • Anaerobic ammonium oxidation in a bioreactor treating slaughterhouse wastewater Biotechnology

    Reginatto, V.; Teixeira, R. M.; Pereira, F.; Schmidell, W.; Furigo Jr, A.; Menes, R.; Etchebehere, C.; Soares, H. M.

    Resumo em Inglês:

    Ammonium oxidation was thought to be an exclusively aerobic process; however, as recently described in the literature, it is also possible under anaerobic conditions and this process was named ANAMMOX. This work describes the operation of a system consisting of a denitrifying reactor coupled to a nitrifying reactor used for removal of nitrogen from slaughterhouse wastewater. During operation of the denitrifying reactor an average nitrogen ammonium removal rate of 50 mg/Ld was observed. This biomass was used to seed a second reactor, operated in repeated fed batch mode, fed with synthetic medium specific to the growth of bacteria responsible for the ANAMMOX process. The nitrogen loading rate varied between 33 and 67 mgN/Ld and average nitrogen removal was 95% and 40%, respectively. Results of fluorescence in situ hybridization (FISH) confirmed the presence of anammox-like microorganisms in the enriched biomass.
  • A full-scale UASB reactor for treatment of pig and cattle slaughterhouse wastewater with a high oil and grease content Environmental Engineering

    Miranda, L. A. S.; Henriques, J. A. P.; Monteggia, L. O.

    Resumo em Inglês:

    This paper discusses the performance of an 800m³ full-scale UASB reactor in treating meat-packing plant and slaughterhouse effluents containing high concentrations of oil and grease (O&G) (413-645 mg/L), resulting in a COD/O&G ratio of 26-32%. Those macromolecules were considered responsible for the unbalance of the system resulting in a total washout of the biomass. The removal of O&G from the influent using a physicochemical system (coagulation-flocculation) improved the physical characteristics of the anaerobic sludge, controlling the biomass washout. Reactor performance was significantly improved when the COD/O&G ratio influent was maintained in the 10%. The COD and O&G removal rates obtained after implantation of the physicochemical system were 70-92% and 27-58%, respectively. The specific methanogenic activity (SMA) of the biomass shows towards a tendency stabilisation and adaptation to the substrate influent. Pretreatment of the influent allowed the maximum organic load to be increased (1.46 to 2.43 Kg COD/m³.d) and improved the quality of the effluent.
  • Assessment of the ability of sludge to degrade PCP under anaerobic conditions Environmental Engineering

    Bolaños, R. M. L.; Damianovic, M. H. R. Z.; Zaiat, M.; Foresti, E.

    Resumo em Inglês:

    The capacity of sludge from different sources to degrade pentachlorophenol (PCP) was evaluated. Three 2.5 liter reactors (R1, R2, and R3) were inoculated with different anaerobic sludges, semi continuously fed and maintained in orbital motion at 30±1°C. R1 was inoculated with aerobic sludge and river sediment collected downstream from a pulp and paper plant. R2 received sludge from an anaerobic reactor treating effluents from a paper recycling plant and R3 received anaerobic sludge from a biodigestor treating industrial and domestic effluents. The sludges were first acclimatized to a culture medium generally recommended for organochloride anaerobic degradation studies. The reactors were then subjected to increasing concentrations of PCP from 0.05 to 10.0 mg.l-1. PCP degradation and metabolite formation were monitored using gas chromatography, and the effects of PCP on the anaerobic process were verified by monitoring pH, volatile fatty acids, alkalinity, total suspended solids, and chemical oxygen demand. It was found that PCP did not affect reactor performance. All the sludges displayed the best PCP degradation capacity at a concentration of 0.2 mg.l-1, producing fewer chlorinated metabolites than when higher PCP concentrations were applied. R1 consistently produced fewer chlorinated metabolites, confirming the hypothesis that pre exposure to chlorinated compounds improves the sludge's capacity to degrade PCP.
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