RESUMO O objetivo deste estudo foi avaliar a produção de enzimas amilolíticas, celulolíticas e proteolíticas pela linhagem Penicillium spp. LEMI A8221 cultivada em estado sólido em resíduos da colheita de soja, ao longo de quatro dias, em diferentes condições de pH (5,0 e 6,0), temperatura (30 e 35°C) e concentrações de substrato (70 e 90% p/v). As atividades máximas obtidas para α-amilase, β-amilase, CMCase e protease foram de 0,20; 0,13; 0,65 e 147 U.mg-1, respectivamente. As condições de fermentação influenciaram a atividade das enzimas, sendo a concentração de substrato, a variável mais significativa para o processo. O tempo de fermentação exerceu efeito apenas para as atividades de amilase sacarificante e CMCase, sendo registrados os menores valores de atividade para essas enzimas, nas primeiras 24 e 48 horas de fermentação, respectivamente. Conclui-se que o isolado Penicillium spp. LEMI A8221 pode ser considerado promissor agente biológico, com aplicação industrial, e o resíduo de soja apresentou-se como fonte de carbono alternativa, no cultivo em estado sólido, para produção de enzimas por esta linhagem microbiana.

ABSTRACT The aim of this study was to quantify the enzymatic activity of amylolytic, cellulolytic and proteolytic enzymes produced by the fungi strain Penicillium spp. LEMI A8221 under solid state culture in soybean crop residues, during 4 days, in different conditions of pH (5.0 and 6.0), temperature (30 and 35 °C) and substrate concentration (70 and 90% p/v). The maximum activity obtained for α-amylase, β-amylase, protease and CMCase were 0.20; 0.13; 0.65 and 147 U.mg-1, respectively. The fermentation conditions influenced the enzyme activity, being substrate concentration, the most significant variable to the process. The fermentation time exerted effect only for the activities of CMCase and β-amylase being recorded smaller values for these enzymes in the first 24 to 48 hours of fermentation, respectively. It is concluded that the isolated Penicillium spp. LEMI A8221 can be considered a promising biological agent with industrial application and soybean residue was presented as an alternative carbon source in solid-state cultivation for enzyme production by microbial strain.

The objective of this study was to evaluate the effect of bacterial inoculants at two inoculation rates on chemical and biological characteristics of maize silage. The treatments consisted of two inoculating rates (5 and 6 log cfu g-1of forage) for each strain of lactic acid bacteria (LAB) identified as Lactobacillus buchneri, L. hilgardii, or L. plantarum. The maize was ensiled in experimental PVC silos. Samples were taken for the determination of the contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), water-soluble carbohydrates (WSC), organic acids and alcohols, for the evaluation of the populations of lactic acid bacteria, yeasts, filamentous fungi, and for the determination of pH values during ensilage and after 30 or 90 days of fermentation. The doses of inoculants did not promote significant differences on the evaluated characteristics. There was effect of inoculants on acetic acid, 1.2-propanediol, LAB population, filamentous fungi, and pH value. No significant influence of the treatments with inoculants was observed in the variables DM, WSC, CP, lactic acid concentrations, or ethanol. The maximum temperature, i.e., the time to achieve the maximum temperature (TMT) and aerobic stability (AS), was not influencied by treatments. However, a decrease in maximum temperature, an increase in TMT, and improvement in the AS were observed after 90 days of fermentation. These results proved the advantage of microbial inoculation. The treatments influenced LAB populations and filamentous fungi, but no effect was observed on the yeast population. The best inoculation dose is 6 cfu g-1 of forage because it provides higher reduction of filamentous fungi in maize silage, thereby decreasing the aerobic deterioration by these microorganisms.