Growth and proximate composition of Pleurotus ostreatuscultivated on green bocaiuva pulp substrates with different nitrogen sources

The aim of this work was to evaluate the growth and the proximate compositionof the mycelium-based bocaiuva pulp with the edible mushroom Pleurotusostreatuson green bocaiuva flour added with different sources of nitrogen (urea, ammonium nitrate and sulfate ammonia). Growth was monitored by kinectics. At the end, the proximate composition of the best three treatments (dehydrated green bocaiuva pulp and water, T1; dehydrated green bocaiuva pulp and ammonium nitrate, T3; and green bocaiuva pulp/wheat bran and ammonium nitrate, T7) was determined. Ammonium nitrate was the nitrogen source that showed the greatest growth in both substrates (T3:8.33 cm and T7:7.67 cm) in relation to the other treatments (4.67 to 7.17 cm), with emphasis on the green bocaiuva pulp. The substrate with green bocaiuva pulp and water was the one that showed the highest growth (7.50 cm), which was close to the treatment with mixed substrate and ammonium nitrate (7.67 cm). The treatment with the green bocaiuva pulp and ammonium nitrate (T3) was highlighted due to its significant increase in proteins (9.42 g 100 g-1) and fibers (5.21 g 100 g-1), and decrease in carbohydrates (9.52 g 100 g-1), in comparison to the other treatments T7 (8.94, 2.16, and 5.99 g 100 g-1, respectively) and T1 (2.78, 4.33, and 2.28 g 100 g-1, respectively). The product obtained from the growth of P. ostreatusin green bocaiuva pulp presents promising perspectives to be utilized as raw material for the development of new food products with added nutritional value.

Production and characterization of a thermostable ß-glucosidase from Myceliophthora heterothallica / Produção e caracterização de uma ß-glicosidase termoestável de Myceliophthora heterothallica

The conversion of biomass from agro-industrial residues into bioproducts is of great interest, especially to Brazil, where bioenergy has a huge potential for development. Enzymes involved in biodegradation of lignocellulosic biomass are those of the cellulase system, of which ß-glucosidase is a constituent. The production and characterization of ß-glucosidase by the thermophilic fungus Myceliophthora heterothallica by solid-state cultivation on different agro-industrial residues (sugarcane bagasse, sugarcane straw, wheat bran and a mixture of these three materials (1:1:1 w/w) was evaluated. Solid-state cultivation were conducted in 250 mL Erlenmeyer flasks, with 5 g of each substrate. Different culture parameters, such as supplementary nutrient solution to the substrate, supplementary nutrient solution pH, initial substrate moisture and fungus incubation temperature, were evaluated to establish conditions of higher enzyme production by the fungus The greatest production of enzymes occurred in a mixture of wheat bran, sugarcane bagasse and straw bagasse (1:1:1). The activity of ß-glucosidase was greater under the following conditions: nutrient solution composed of NH4NO3, MgSO4.7H2O and (NH4)2SO4 (0.1%), at pH 4.5 or 6.0, fungus incubation at 40°C or 45°C, initial moisture of substrate at 80%. Enzyme presented optimum pH at pH 5.0 and good pH stability. Best temperature was 65°C and enzyme showed 100% stability for 1h, up to 60°C. The use of agro-industrial residues provided good production of ß-glucosidase by fungus, with enzyme having the characteristics desirable from the industrial application.

A conversão da biomassa vegetal proveniente de resíduos agroindustriais em bioprodutos é de grande interesse, principalmente para o Brasil, onde a agroenergia possui grande potencial de desenvolvimento. Enzimas envolvidas na biodegradação da biomassa lignocelulósica fazem parte do grupo das celulases, no qual a 훽-glucosidase é um constituinte. O presente estudo avaliou a produção e caracterização de uma ß-glicosidase pelo fungo termofílico Myceliophthora heterothallica por cultivo em estado sólido de diferentes resíduos agroindustriais (bagaço de cana-de-açúcar, palha de cana-de-açúcar, farelo de trigo e em uma mistura dos três materiais (1:1: 1 p/p). O cultivo em estado sólido foi realizado em frascos Erlenmeyer de 250 mL, contendo 5 g de cada substrato. Diferentes parâmetros de cultivo, como solução nutriente suplementar ao substrato, pH da solução nutriente suplementar, umidade inicial do substrato e temperatura de incubação do fungo foram avaliados, visando estabelecer condições para maior produção da enzima pelo fungo. A maior produção da enzima ocorreu na mistura de farelo de trigo, e bagaço e palha de cana-de-açúcar (1:1:1). A atividade da ß-glicosidase foi maior nas seguintes condições: solução nutriente composta por NH4NO3, MgSO4.7H2O e (NH4)2SO4 (0,1%) com pH 4,5 e 6,0, temperatura de incubação do fungo a 40°C e 45°C, com umidade inicial do substrato em 80%. A enzima apresentou pH ótimo de 5,0, e boa estabilidade ao pH. A temperatura ótima foi de 65°C, e a enzima apresentou 100% de estabilidade por 1h, até 60°C. A utilização de resíduos agroindustriais proporcionou boa produção de ß-glicosidase pelo fungo, com a enzima apresentando características desejáveis para aplicação industrial.

A method to estimate the biomass of Spirulina platensis cultivated on a solid medium

This paper presents a method to estimate the biomass of Spirulina cultivated on solid medium with sugarcane bagasse as a support, in view of the difficulty in determining biomass concentrations in bioprocesses, particularly those conducted in semi-solid or solid media. The genus Spirulina of the family Oscillatoriaceae comprises the group of multicellular filamentous cyanobacteria (blue-green microalgae). Spirulina is used as fish feed in aquaculture, as a food supplement, a source of vitamins, pigments, antioxidants and fatty acids. Therefore, its growth parameters are extremely important in studies of the development and optimization of bioprocesses. For studies of biomass growth, Spirulina platensis was cultured on solid medium using sugarcane bagasse as a support. The biomass thus produced was estimated by determining the protein content of the material grown during the process, based on the ratio of dry weight to protein content obtained in the surface growth experiments. The protein content of the biomass grown in Erlenmeyer flasks on surface medium was examined daily to check the influence of culture time on the protein content of the biomass. The biomass showed an average protein content of 42.2%. This methodology enabled the concentration of biomass adhering to the sugarcane bagasse to be estimated from the indirect measurement of the protein content associated with cell growth.