Produção, Caracterização de xilanase extracelular por Penicillium brefeldianum utilizando bagaço de cervejaria e sua aplicação

Abstract

The production of xylanolitic enzymes have been widely explored in the past few years by several species of filamentous fungi. The objective of this study was to evaluate the production of xylanases by Penicillium brefeldianum an isolated filamentous fungus of Parana Atlantic Forest using brewers spent grain and evaluate its potential in the agro-waste saccharification. The enzyme extract was obtained from liquid culture using 1% (w / v) brewers spent grain in modified under stationary conditions at 28 ° for 9 days. The fungus had large capacity in the production of xylanase (830 U mL-1), pectinase (295 U mL-1), β-xylosidase (3,46 U mL-1), FPase (0,60 U mL-1), avicelase (13, 71 U ml-1), cellulase (1.89 U mL-1) and β -glycosidase (29,45 U mL-1). The optimum pH of 4.5 was found for xylanase and stability in 98% range of 2.5 to 8.0 for 96 hours. The optimum temperature was 55 °C with a half life of 90 minutes. The zymogram of the crude extract of P. brefeldianum exhibited three bands of xylanase activity with molecular masses of 60 and 97kDa. P. brefeldianum crude enzymatic extract was used for saccharification of various waste (sugarcane bagasse, brewers spent grain, rice straw, corn stover, wheat straw, sorghum biomass and sorghum low-lignin) untreated and previously treated with NaOH 30°C for 12h (NaOH30) and at 121°C for 30 minutes (NaOH121). The best results were obtained with waste treated under high pressure and temperature (121°C). Among waste, wheat straw showed higher amount of total sugar (63%) released after the enzymatic hydrolysis, followed brewers spent grain (60%), corn straw (58%), sorghum biomass (54%) and sorghum low-lignin (35%). The pentose released after saccharification showed that sorghum low-lignin treated at high temperature and pressure was the best substrate releasing 7,35 times more pentose compared to sorghum low-lignin untreated, followed by straw rice (5,52x) and sorghum biomass (4,39x). Thus, the filamentous fungus P. brefeldianum isolated from the West of Paraná Atlantic Forest was able to use the brewers spent grain as inductor of various degrading enzymes the cell wall, and furthermore, showed potential for saccharification of lignocellulosic biomass from agro-waste.