Produção de L-asparaginase de Penicillium sp. em espuma de poliuretana em diferentes biorreatores

Abstract

L-asparaginase is an enzyme of fundamental importance in the treatment of cancer and is also useful in the food industry in the control of acrylamide in foods processed at high temperatures. Due to the importance of L-asparaginase, research for new microorganisms capable of producing it and the use of solid-state fermentation have been investigated. In this master’s dissertation, the Penicilliumsp. LAMAI 505 was used in the production of L-asparaginase by solid-state fermentation (SSF). The dissertation investigated: a) influence of temperature, pH and concentrations of glucose and asparagine and inocullumsize in asparginase production; b) optimized L-asparaginase production by Artificial Neural Networks (ANN) method and Genetic Algorithm (GA); c) and evaluated L-asparaginase production using novel bioreactors by recycling media and re-using cells. It was observed: a) three-layer ANN model containing 18 neurons in hidden layer presented satisfactory description of L-asparaginase production (R² = 0.99 for the training stage and R² = 0.98 in validation stage); b) under optimized conditions (16.96 mL of nutrient medium/g of solid support, 1.0 g/L of L-asparagine, 5.24 g/L of glucose, pH equal to 5.0 and temperature of 44.3 ◦C) the activity of L-asparaginase was 3411.6 U/kg, which was 1.61 times higher than the best value obtained with no optimized conditions; c) the recycle rate of 2.0 mL/min at 48 h provided the maximum activity of 3716.7 U/kg of solid support (9.3%higher than the activity in static bioreactor); d) the L-asparaginase production in five re-use cycles of Penicillium sp. LAMAI 505 cells and inert support provided L-asparaginase activity of 6050.0 U/kg of solid support in the third cycle and average activity 3878.0 U/kg of solid support for five reuse cycles, representing a mean increase of the five reuse cycles of 14.1 % in relation to the static bioreactor. Results indicate that the production of L-asparaginase from Penicillium sp. by FES with inert support (FES-SI) is satisfactory when compared with production found in the literature in studies with other species of fungi under optimized conditions, which suggests that the production of L-asparaginase from Penicillium sp. LAMAI 505 is of great importance for the development of this commercial sector.