Electrospinning was used to produce poly(vinyl alcohol) (PVA)-based nanofibers containing nerolidol (NER) as the antimicrobial agent. The scanning electron microscopy results indicated the formation of homogeneous fibers in the absence of NER. However, its incorporation into the fiber prevented the complete solvent evaporation, ultimately leading to the coalescence of the fibers. It became more evident as the amount of NER increased from 0 to 50% m/v. The incorporation of NER also decreased the crystallinity of the fibers from 10 to ca. 6.5%. However, this decrease was not proportional to the concentration of NER. The contact angle results confirmed the presence of NER molecules on the surface of the fibers especially due to the increase of the contact angle from 0 (PVA/NER0) to 27.8º (PVA/NER50). The fibrous mats exhibited good antimicrobial activity, being even more efficient than the control in some cases, suggesting their potential for wound-dressing purposes.

Abstract Iron and zinc bioaccumulation in mycelial biomass of different medicinal basidiomycetes was evaluated in order to produce metal-enriched mycelial biomass as an alternative functional food from non-animal sources and based on biotechnology processes. Pleurotus ostreatus strain U2-9, U2-11, U6-8, and U6-9, Pleurotus eryngii strain U8-11, Schizophyllum commune strain U6-7, and Lentinula edodes strain U6-11 and U6-12 were grown in malt extract agar with or without addition of 50 mg/L iron or 7.5 mg/L zinc. The mycelial biomass was separated and iron and zinc concentrations were determined in a flame atomic absorption spectrophotometer. Basidiomycete strains presented different growth rates with the presence of iron and zinc; there was no dependence between the metal bioaccumulation and the fungal growth. The fungi presented greater capacity to bioaccumulate iron than zinc. P. ostreatus (U2-9) has greater iron bioaccumulation (3197.7 mg/kg) while P. ostreatus (U6-8) greater zinc bioaccumulation (440.4 mg/kg) in mycelial biomass. P. ostreatus (U2-9), P. ostreatus (U2-11), and S. commune (U6-7) had the highest metal translocation rates from the culture medium to mycelial biomass. The mycelial biomass enriched with iron or zinc is an alternative to a new functional food from non-animal sources.

Abstract Sugarcane crop conventional tillage has been replaced by deep soil preparation with few studies about its effect on soil quality and sustainability. The aim of this study was to assess structural volumes ina dystrophic Red-Yellow Latosol subjected to conventional tillage (CT) and deep localized soil tillage (DLST) to verify how the microbiological parameters were affected. The study was conducted in a soil derived from the Caiuá Sandstone formation in Brazil. Four trenches were dug for each soil tillage system to describe the cultural profile and evaluate carbon microbial biomass (CMB) and nitrogen (NMB), basal respiration (BR), and metabolic quotient (qCO2). CT profiles exhibited a predominance of cracked soil volumes, medium-sized and large compact clods with some porosity, and continuous volumes with no cracks and of intermediate porosity. DLST profiles were predominantly free-soil volume with no cohesion and porous in appearance, and compact, cohesive volumes with no porosity visible. The highest levels of CMB and NMB were in the cracked soil under CT. Higher microbial activity indicated by BR and qCO2 were in the free powdery soil under DLST. Soil pulverization caused by DLST could cause serious consequences on soil functionality, boosting erosion, and metabolic stress in the microbiota.

ABSTRACT Lentinus crinitus is a white-rot fungus that produces laccase, an enzyme used for dye decolorization. Enzyme production depends on cultivation conditions, mainly agro-industrial by-products. We aimed to produce laccase from Lentinus crinitus with agro-industrial by-products for dye decolorization. Culture medium had coffee husk (CH) or citric pulp pellet (CP) and different nitrogen sources (urea, yeast extract, ammonium sulfate and sodium nitrate) at concentrations of 0, 0.7, 1.4, 2.8, 5.6 and 11.2 g/L. Enzymatic extract was used in the decolorization of remazol brilliant blue R. CH medium promoted greater laccase production than CP in all evaluated conditions. Urea provided the greatest laccase production for CH (37280 U/L) as well as for CP (34107 U/L). In CH medium, laccase activity was suppressed when carbon-to-nitrogen ratio changed from 4.5 to 1.56, but the other nitrogen concentrations did not affect laccase activity. For CP medium, reduction in carbon-to-nitrogen ratio from 6 to 1.76 increased laccase activity in 17%. The peak of laccase activity in CH medium occurred on the 11th day (41246 U/L) and in CP medium on the 12th day (32660 U/L). The maximum decolorization within 24 h was observed with CP enzymatic extract (74%) and with CH extract (76%).

ABSTRACT Antitumor activity of Agaricus subrufescens has been shown on vegetative mycelium and basidiocarp. However, few studies have assessed the effect of A. subrufescens cultivation conditions and extraction methods on antitumor activity. This study evaluated the effect of nitrogen concentration on the cultivation medium of A. subrufescens and the extraction method of mycelial antineoplastic actives against sarcoma 180 cells implanted in mice. Two nitrogen sources (isolated soybean protein and NaNO3) and 10 nitrogen concentrations (0.25 to 8.0 g/L) were used. Dried mycelium extract was obtained by hot water infusion (1:10 mass:volume; 90 °C) or by aqueous mixture (1:10 mass:volume, ambient temperature) in ultrapure water. The doses were administered daily by gavage to mice implanted with sarcoma 180 cells. Isolated soy protein is more efficient to mycelial biomass production than NaNO3. The mycelial biomass production increases when the cultivation medium is added with high nitrogen concentrations as well as the splenic index and the antitumor activity of the moistened mycelial powder. Hot water extract is more effective than the moistened mycelial powder to reduce tumor. The antitumor activity of hot water mycelial extract is similar to the one of basidiocarps, presenting lower metabolic demand on the spleen, keeping blood parameters normal and promoting animal wellness.

Pleurotus ostreatus is able to bioaccumulate several metals in its cell structures; however, there are no reports on its capacity to bioaccumulate iron. The objective of this study was to evaluate cultivation variables to increase iron bioaccumulation in P. ostreatusmycelium. A full factorial design and a central composite design were utilized to evaluate the effect of the following variables: nitrogen and carbon sources, pH and iron concentration in the solid culture medium to produce iron bioaccumulated in mycelial biomass. The maximum production of P. ostreatus mycelial biomass was obtained with yeast extract at 2.96 g of nitrogen L−1 and glucose at 28.45 g L−1. The most important variable to bioaccumulation was the iron concentration in the cultivation medium. Iron concentration at 175 mg L−1 or higher in the culture medium strongly inhibits the mycelial growth. The highest iron concentration in the mycelium was 3500 mg kg−1 produced with iron addition of 300 mg L−1. The highest iron bioaccumulation in the mycelium was obtained in culture medium with 150 mg L−1 of iron. Iron bioaccumulation in P. ostreatus mycelium is a potential alternative to produce non-animal food sources of iron.