Hydrolysis of pineapple crown biomass by cellulolytic enzymes produced by Fusarium oxysporum

Abstract

The development of microbial enzymes is of great importance in biochemical process industries. Among the enzymes of industrial importance, cellulolytic and xylanolytic enzymes stand out, which are responsible for the degradation of lignocellulosic material that is usually discarded by the agro-industrial sector. In order to produce the enzymes CMCase, β-glycosidase, xylanase and β-xylosidase, the fungus Fusarium oxysporum was used in liquid fermentation using pre-treated pineapple crown biomass as a carbon source. In order to optimize the production of these enzymes, cultures were carried out for 168 hours, 30 °C at 180 rpm. The biomass underwent a pre-treatment in two stages, the first being submitted to 121 °C for 7 min, while the second was added diluted sulfuric acid to 1%, in the proportion of 1:5 (m/v), at 121 °C for 27 minutes. The partial characterization of the crude extract showed a temperature of 50 ºC as the most satisfactory for the action of these enzymes, and the ideal pH range ranged from 3.5 to 5.5. The enzymatic hydrolysis of pineapple crown, with and without pretreatment, was performed using lyophilized crude extract (CMCase = 9.78 U/mL, β-glucosidase = 10.86 U/mL, xylanase = 27.90 U/mL and β-xylosidase = 0.018 U/ml). An experimental design of the Central Composite Rotational Design was carried out. It was possible to evaluate the effect and influence of pH, biomass concentration and incubation time on the release of glucose in the medium (R2>0.85); pH and biomass (%) had a significant effect on glucose release.