Produção de celulases e xilanases, em biorreator rotativo com pulsos de ar, pelo Penicillium ucsense S1M29

Abstract

Due to the growing demand for fuels and the increasing presence of policies aimed at reducing the emissions of carbon dioxide the energy matrix, ethanol is emerging as a renewable alternative to fossil fuels. The world's two main raw materials for ethanol production are corn and sugar cane, with Brazil being the world's second largest ethanol producer and mostly using sugar cane for this production. In the production of conventional ethanol, known as first-generation ethanol, a significant volume of lignocellulosic waste is generated from sugar cane straw and bagasse, which can be used to produce second-generation ethanol, or cellulosic ethanol. For this production, enzymes are needed to convert the cellulose and hemicellulose present in lignocellulosic waste into fermentable sugars, which after the fermentation and distillation process will give rise to fuel ethanol. This work focused on solid-state fermentation to produce these enzymes by the fungus Penicillium ucsense using the S1M29 strain, employing sugar cane bagasse (SCB) and wheat bran (WB) as substrates, plus a salt solution, in a rotating drum with 5,7 liters, with the application of pressure pulses and air decompression, as an additional mechanism for controlling the temperature of the bioreactor. The results show the efficiency of the process of applying pressure pulses to change the temperature of the bioreactor. The best results in the cultivations without pressure pulses were with the ratio of 65 SCB: 35 WB, achieving 16 FPU g-1 of dry mass for total cellulases, 78 U g-1 of dry mass for endoglycanases, 96 U g-1 of dry mass for ß-glucosidases and 324 U g-1 of dry mass for xylanases. For the cultivations in the presence of pressure pulses the results for FPA and endoglycanases were higher for 50 SCB: 50 WB, reaching 17 FPU g-1 dry mass and 90 U g-1 dry mass respectively, and for ß-glucosidases and xylanases were better with 65 SCB: 35 WB, reaching values of 121 U g-1 dry mass and 277 U g-1 dry mass respectively. The data showed the production of cellulases and xylanases in solid-state cultivation in a benchtop bioreactor, open the possibility of carrying out pilot-scale studies. [resumo fornecido pelo autor]