Produção e caracterização parcial de proteases a partir de Mucor hiemalis URM3773 / Production and partial characterization of proteases from Mucor hiemalis URM3773

Foi avaliada a produção de proteases por 11 espécies fúngicas pertencentes aos gêneros Mucor, Rhizomucor e Absidia, obtidas da Coleção de Culturas URM do Departamento de Micologia-UFPE, Brasil. A melhor espécie produtora foi Mucor hiemalis URM3773 (1,689 U mL-1). A metodologia de planejamento Plackett-Burman foi empregada para selecionar o parâmetro mais efetivo para a produção de proteases através de 11 componentes do meio, incluindo: concentração do filtrado de soja, glicose, período de incubação, extrato de levedura, triptona, pH, aeração, rotação, NH4Cl, MgSO4 e K2HPO4. A variável significante sobre a variável-resposta, atividade proteásica específica, foi a concentração do filtrado de soja. O extrato enzimático bruto apresentou atividade ótima ao pH 7,5 a 50ºC. A enzima foi estável em uma ampla variação de pH de 5,88,0 em tampão fosfato 0,1M e termicamente estável a uma variação de 40- 70C, durante 180 minutos. Os íons FeSO4, NaCl, MnCl2, MgCl2 e KCl estimularam a atividade proteásica, enquanto que o íon ZnCl2 inibiu 2,27% da atividade. O inibidor de proteases que teve maior ação foi o ácido iodoacético a 1mM. Os resultados obtidos indicam que a enzima estudada tem grande potencial de aplicação industrial.(AU)

The current study evaluated the proteases production from 11 fungal species belonging to the genera Mucor, Rhizomucor and Absidia. The species were obtained from the Collection of Cultures URM at the Mycology Department-UFPE, Brazil. The best producing species was Mucor hiemalis URM 3773 (1.689 U mL-1). Plackett-Burman design methodology was employed to select the most effective parameter for protease production out of 11 medium components, including: concentration of filtrate soybean, glucose, incubation period, yeast extract, tryptone, pH, aeration, rotation, NH4Cl, MgSO4 and K2HPO4. Filtrated soybean concentration was the significant variable over the response variable, which was the specific protease activity. The crude enzyme extract showed optimal activity in pH 7.5 and at 50ºC. The enzyme was stable within a wide pH range from 5.8 to 8.0, in the phosphate buffer 0.1M and in stable temperature variation of 40-70ºC, for 180 minutes. The ions FeSO4, NaCl, MnCl2, MgCl2 and KCl stimulated the protease activity, whereas ZnCl2 ion inhibited the activity in 2.27%. Iodoacetic acid at 1mM was the proteases inhibitor that presented greater action.The results indicate that the studied enzyme have great potential for industrial application.(AU)

Agroforestry systems, nutrients in litter and microbial activity in soils cultivated with coffee at high altitude

Agroforestry systems are an alternative option for sustainable production management. These systems contain trees that absorb nutrients from deeper layers of the soil and leaf litter that help improve the soil quality of the rough terrain in high altitude areas, which are areas extremely susceptible to environmental degradation. The aim of this study was to characterize the stock and nutrients in litter, soil activity and the population of microorganisms in coffee (Coffea arabica L.) plantations under high altitude agroforestry systems in the semi-arid region of the state of Pernambuco, Brazil. Samples were collected from the surface litter together with soil samples taken at two depths (0-10 and 10-20 cm) from areas each subject to one of the following four treatments: agroforestry system (AS), native forest (NF), biodynamic system (BS) and coffee control (CT).The coffee plantation had been abandoned for nearly 15 years and, although there had been no management or harvesting, still contained productive coffee plants. The accumulation of litter and mean nutrient content of the litter, the soil nutrient content, microbial biomass carbon, total carbon, total nitrogen, C/N ratio, basal respiration, microbial quotient, metabolic quotient and microbial populations (total bacteria, fluorescent bacteria group, total fungi and Trichoderma spp.) were all analyzed. The systems thatwere exposed to human intervention (A and BS) differed in their chemical attributes and contained higher levels of nutrients when compared to NF and CT. BS for coffee production at high altitude can be used as a sustainable alternative in the high altitude zones of the semi-arid region in Brazil, which is an area that is highly susceptible to environmental degradation.

Agroforestry systems, nutrients in litter and microbial activity in soils cultivated with coffee at high altitude

Agroforestry systems are an alternative option for sustainable production management. These systems contain trees that absorb nutrients from deeper layers of the soil and leaf litter that help improve the soil quality of the rough terrain in high altitude areas, which are areas extremely susceptible to environmental degradation. The aim of this study was to characterize the stock and nutrients in litter, soil activity and the population of microorganisms in coffee (Coffea arabica L.) plantations under high altitude agroforestry systems in the semi-arid region of the state of Pernambuco, Brazil. Samples were collected from the surface litter together with soil samples taken at two depths (0-10 and 10-20 cm) from areas each subject to one of the following four treatments: agroforestry system (AS), native forest (NF), biodynamic system (BS) and coffee control (CT).The coffee plantation had been abandoned for nearly 15 years and, although there had been no management or harvesting, still contained productive coffee plants. The accumulation of litter and mean nutrient content of the litter, the soil nutrient content, microbial biomass carbon, total carbon, total nitrogen, C/N ratio, basal respiration, microbial quotient, metabolic quotient and microbial populations (total bacteria, fluorescent bacteria group, total fungi and Trichoderma spp.) were all analyzed. The systems thatwere exposed to human intervention (A and BS) differed in their chemical attributes and contained higher levels of nutrients when compared to NF and CT. BS for coffee production at high altitude can be used as a sustainable alternative in the high altitude zones of the semi-arid region in Brazil, which is an area that is highly susceptible to environmental degradation.(AU)