Cellulase production to obtain biogas from passion fruit (Passiflora edulis) peel waste hydrolysate

Abstract

Enzyme usage for valorization of organic and agroindustrial wastes is a biotechnology field that had been increasing due to economic and environmental benefits that add to productive cycles. Enzymatic hydrolysis is one of the possible pre-treatments used with the aim of facilitating lignocellulosic waste biodigestion. This work evaluated cellulase production by Aspergillus japonicus URM5620 and its use as enzymatic pre-treatment on passion fruit peel waste (Passiflora edulis) in order to facilitate the anaerobic biodigestion for biogas generation purposes. Cellulases were produced by submerged fermentation, being maximized using a factorial 2² design, analysing substrate concentration (passion fruit peel) (1.0 to 3.0%) and glucose (0.5 to 1.0%). Enzymatic hydrolyzate obtained from submerged fermentation was biodigested in anaerobic reactor, in a laboratory scale. The highest activities of 1.2 U/mL total cellulase (FPase) and 1.7 U/mL endoglucanase (CMCase) were obtained at 3% of substrate and 1% of glucose. Biogas production from hydrolyzed waste provided methane with a concentration of above 64% by volume after 15 days. Fermentation pre-treatment, using Aspergillus japonicus, was a step that potentially facilitates and accelerates lignocellulosic organic waste biodigestion.