Produção de l-asparaginase fúngica em fermentação em estado sólido utilizando reatores com tecnologia de materiais poliméricos

Abstract

The L-asparaginase enzyme is of fundamental importance in the production of drugs used in the treatment of cancers and hematopoietic diseases, in addition, it is very useful in food industry in the control of acrylamide in foods processed at high temperatures. Much of the L-asparaginase produced is still from a bacterial source in process submerged fermentation (SmF), however the use of fungi capable of producing L-asparaginase in solid-state fermentation (SSF) gains more attention, along with the development of new SSF bioreactors capable of producing fungal L-asparaginase for long periods of operation. Due to the importance of the L-asparaginase enzyme and the scarcity of papers describing new SSF bioreactors in the continuous production of fungal L-asparaginase, two new SSF bioreactors capable of continuously producing L-asparaginase have been investigated: the multi-phase reactor with cell immobilization (MRIC) and modular reactor with technology polymeric (MRPT). Regarding the MRIC, the reactor was optimized considering the variables temperature, pH and concentrations of glucose and L-asparagine, residence time and time of fermentation using an artificial neural network (ANN) model associated with the model of genetic algorithm( GA), being proposed a system of multiple reactors (MRICs) for produce L-asparaginase by Penicillium sp. LAMAI 505, Aspergillus sp. and Fusarium sp. in SSF for long periods of operation. The MRICs system has been optimized considering the effects of the number of associated reactors, nutrient composition, residence time, recycling of nutrients and extraction cycles using ANN and GA. The ANN model was satisfactory (R²>0.85 with an error less than 2.4%) and the MRICs performed well when compared to the literature. The maximum L-asparaginase activity achieved was 13.7 U/g under conditions optimized which included a residence time of 33.5 min, pH of 5.1 and concentrations of L-asparagine and glucose 1.2 and 3.0 g/L, respectively. In addition, we demonstrate that the MRICs are effective with other fungi and can be used for other products. Referent to MRPT has developed a new reactor for the production of L-asparaginase from Penicillium sp. LAMAI 505 is capable of operating in batch and continuous processes for long periods of operation. The data obtained in the MRPT reactor were adjusted and optimized with ANN and the differential evolution method (DE) obtaining an L-asparaginase yield of 19.36 U/g and 6.78 U/g.h under optimized conditions of continuous operation at 25 °C, 5.27 g/L of L-asparagine, 5.34 g/L of glucose and pH 6.03. In addition, we have demonstrated that the MRPT is capable of achieving the L-asparaginase yield for long-term operation (more than 1000 h). The results indicate that the production of L-asparaginase by SSF using the two new bioreactors is satisfactory when compared to the products found in the literature, which suggests that the new reactors are capable of producing fungal L-asparaginase in batch SSF and operating continuously.