Félix Gonçalves de Siqueira

Cultivation of Agaricus blazei ss. Heinemann using different soils as source of casing materials.

Commercial productivity of the Agaricus blazei mushroom is closely related to both the quality of the compost and the choice of soil to be used as a casing material. This study aims to evaluate Agaricus blazeis productivity using two compost formulations and three soils. The two compost formulations were (i) crushed sugarcane bagasse (Saccharum officinarum (L.)) and Coastcross hay (Cynidon dactylon (L.) Pers.), and (ii) crushed sugarcane bagasse (Saccharum officinarum (L.)) and corn husk (Zea mays L.); they were amended with wheat bran, lime, gypsum, superphosphate and urea. The casing materials were extracted from three soils classed as Rhodic Hapludox, Xanthic Hapludox, and Humic Haplaquox. The Rhodic Hapludox soil material was mixed with fragments of Eucalyptus charcoal in the proportion of 4:1. The compost was prepared during six weeks and thereafter heat treated during 48 h at the end of the composting period. The sugarcane bagasse:coast-hay compost was superior to the sugarcane bagasse: corn husk compost. The Rhodic Hapludox plus charcoal casing material showed to be a better casing material than either the Xanthic Hapludox and Humic Haplaquox soil materials. The choice of the soils where the casing material is taken is an important factor to the success of the Agaricus blazei mushroom cultivation.

Biological efficiency of Agaricus brasiliensis cultivated in compost with nitrogen concentrations

The production of compost is one of the most important steps for the cultivation of any species of mushroom. For the Agaricus species, this step is even more complex because it depends on the performance of different microorganisms that act on the substrate, turning it into selective compost that promotes the growth of the fungus to be cultivated. Among the various factors that affect the microbial activity, the initial concentration of nitrogen is considered one of the most important. Due to the lack of conclusive studies about that, the aim of this study was to evaluate the productivity and biological efficiency of Agaricus brasiliensis in compost prepared with different initial concentrations of nitrogen, according to the composting methodology and to the conventional pasteurization techniques (phase I and II). Three initial nitrogen concentrations (w/w) (T 1 = 1.0%; T 2 = 1.5%; and T 3 = 2.0%) were tested and mycelial growth was determined in terms of mm/day for all treatments. The productivity and biological efficiency were also determined. The most efficient initial concentrations of nitrogen were of 1.0% and 1.5%. This concentration of N in the compost permitted a faster development of the mushroom with higher productivity when compared to the results obtained with the application of 2% of nitrogen.

The hydrolysis of agro-industrial residues by holocellulose-degrading enzymes

Holocellulose structures from agro-industrial residues rely on main and side chain attacking enzymes with different specificities for complete hydrolysis. Combinations of crude enzymatic extracts from different fungal species, including Aspergillus terreus, Aspergillus oryzae, Aspergillus niger and Trichoderma longibrachiatum, were applied to sugar cane bagasse, banana stem and dirty cotton residue to investigate the hydrolysis of holocellulose structures. A. terreus and A. oryzae were the best producers of FPase and xylanase activities. A combination of A. terreus and A. oryzae extracts in a 50% proportion provided optimal hydrolysis of dirty cotton residue and banana stem. For the hydrolysis of sugar cane bagasse, the best results were obtained with samples only containing A. terreus crude extract.

Cultivation of Pleurotus sajor-caju on banana stalk and Bahia grass based substrates

Banana stalks and Bahia grass were utilized as basic starting materials for the production of the mushroom Pleurotus sajor-caju. Banana stalks were combined with other waste or supplement products (wheat bran, coast-cross hay, bean straw and cotton textile mill) to obtain different nitrogen concentrations. Since Bahia grass is relatively rich in protein, it was combined with other substrates (banana stalk, coast-cross hay and bean straw) to maintain a substrate nitrogen concentration of about 1.5%. Banana stalks and Bahia grass were both more efficient in the production of the mushroom P. sajor-caju when utilized without the addition of other substrates, with biological efficiencies of 74.4% and 74.12%, respectively. When combined with other substrates or grasses, there was a drop in biological efficiency, independent of the concentration of nitrogen. Furthermore, the addition of protein-rich waste to banana stalks resulted in a decrease or absence of fructification, which indicates that high concentrations of nitrogen in the cultivation substrate may hinder the cultivation of this mushroom. On the other hand, results reveal that the ideal concentration of nitrogen may depend on other physicochemical factors and these factors may determine the success in cultivating P. sajor-caju. Therefore, we conclude that P. sajor-caju may be cultivated on banana stalk and Bahia grass as pure substrates, not being necessary their supplementation or combine them with another substrates.

Cultivation of Pleurotus mushrooms in substrates obtained by short composting and steam pasteurization

This paper presents results of two experiments for cultivation of Pleurotus ostreatus , Pleurotus pulmonarius and Pleurotus eryngii grown with different formulations of grass and straw mixtures derived from agro-industrial residues. Cultivation was prepared through a number of approaches, such as short composting/pasteurization and axenic culture. In the first experiment, P. pulmonarius was grown on two formulations of different grasses, with no significant differences observed for either productivity or biological efficiency, with values close to 20 and 60%, respectively. The second experiment revealed similar productivity and biological efficiency between P. pulmonarius and P. ostreatus for both forms of substrate treatment (short composting/pasteurization vs. axenic culture), with similar values to those observed in the first experiment. P. eryngii did not produce mushrooms in the composting treatment and showed lower productivity (17.5%) than the other two species (20.5 and 20.8%, respectively) when the substrates were autoclaved (axenic culture). The preparation for short composting and steam pasteurization was described in illustrative figures in order to provide expertise to small producers who wish to initiate economic and sustainable mushroom cultivation making use of regional lignocellulosic residues. Keywords: Steam pasteurization, lignocellulosic biomass, straw mixtures, mushrooms

Hydrolysis of sugarcane bagasse with enzyme preparations from Acrophialophora nainiana grown on different carbon sources

Abstract The filamentous fungus Acrophialophora nainiana, isolated from a hot spring in Brazil, was grown in liquid culture on different cellulosic and lignocellulosic carbon sources for seven days and enzyme extracts were characterised with respect to their carbohydrase activity profile. The enzyme extracts obtained from growing A. nainiana on cellulose, dirty-cotton residue, sugarcane bagasse and banana stem were used in the hydrolysis of sugarcane bagasse untreated (UT), pre-treated by steam explosion (SET) and pre-treated by acid-catalysed steam explosion (SAT). The carbohydrase activity profile of the enzyme preparations varied significantly with the used carbon source. The highest enzyme activities, especially total cellulase (0.0132 IU) and xylanase (0.0774 IU) activities, were obtained with banana stem as the carbon source. Pectinase activity was produced on all carbon sources at comparable levels. On sugarcane bagasse, total cellulase activity on filter paper and pectinase activities were predominant, but a very low amount of xylanase and CMCase activity, 0.0011 IU and 0.0019 IU, respectively, was found. The exocellulase/endocellulase activity ratio (FPAsol/FPAinsol) of the cellulases produced varied between 1 and 4 depending on the substrate. The highest endocellulase activity (FPAinsol) content was obtained when grown on sugarcane bagasse. Conversions to reducing sugars of the differently pre-treated sugarcane bagasse substrates with enzyme preparations from A. nainiana were in general low. The highest conversion to reducing sugars (˜18%) was obtained for the SET bagasse by the banana stem enzyme preparation, while conversions with the other enzyme preparations were below 5%. In most cases a very low conversion (below 1%) was obtained for the SAT bagasse, but better conversions were achieved for the UT. These results are mainly attributable to the hydrolysis of the hemicellulose fraction and the low cellulase and β-glucosidase activities in the enzyme preparations. Hydrolysis data were also analysed and successfully fitted with a fractal kinetics model, and model parameters are discussed with respect to the carbon source used for A. nainiana enzyme production and substrate pre-treatment.

Development of an RP-UHPLC-PDA method for quantification of free gossypol in cottonseed cake and fungal-treated cottonseed cake

Cottonseed cake biomass, which is a residue of oil extraction, is potentially appropriate for use as animal feed, given the high mineral, fibre and protein content. The presence of free gossypol, however, a toxic pigment in the glands of the cotton plant, limits use of this biomass for monogastric livestock. A promising method to detoxify cottonseed cake relies on fermentation by fungi, which can eliminate up to 100% of gossypol. In order to quantify trace levels of free gossypol in different cotton materials, including cottonseed cake treated with macrofungi, a simple and rapid chromatographic detection method was developed and validated. Under optimized conditions, extraction was performed using 70% acetone. The extract was then analysed by Ultra High-Performance Liquid Chromatography (UHPLC), with gradient elution on a C18 reverse phase column KINETEX® (100 x 2.10 mm, 2.6 μm). Methanol-0.1% TFA aqueous solution was employed as mobile phase and PDA detection conducted at 254 nm. The optimized method was validated by analysis of specificity, linearity and range, limit of detection, limit of quantification, precision and accuracy. Detection and quantification limits were observed at 0.2 and 0.5 μg/mL, respectively. With good reproducibility, with precision (RSD)<10% and recovery greater than 94%, the developed assay was appropriate for quantification of low quantities of free gossypol. The validated method was successfully applied to determine trace levels of free gossypol cottonseed treated with a macrofungus.