Production of Extracellular Enzymes by Lentinula edodes Strains in Solid-State Fermentation on Lignocellulosic Biomass Sterilized by Physical and Chemical Methods.

Abstract

Two methods of sterilization of lignocellulosic biomass were performed in this study. Eucalypt waste (EW) supplemented with rice bran (RB) was added in the proportions 80:20 and 90:10 in dry weight. The compositions were sterilized by physical method (autoclaving) and by chemical method (H2O2). The production of extracellular enzymes by Lentinula edodes strains was compared within the two methods. Inactivation of catalase present in RB was achieved with 250mM H2O2. The use of H2O2, when compared by physical method, favored high production of hydrolytic enzymes such as endoglucanase (1,600IU/kg), twofold higher, β-glucosidase (1,000IU/kg), fivefold higher, xylanase (55,000IU/kg), threefold higher and β-xylosidase (225IU/kg), similar results. Oxidative enzymes, MnP and laccase, were produced within a different profile between strains, with shorter times for laccase (2,200IU/kg) by SJC in 45days and MnP (2,000IU/kg) by CCB-514 in 30days. High production of extracellular enzymes is achieved by the use of the chemical method of sterilization of lignocellulosic biomass; in addition to no energy consumption, this process is carried out in a shorter execution time when compared to the physical process. The use of H2O2 in sterilization does not produce toxic compounds from the degradation of hemicellulose and cellulose such as furfural and hydroxy-methyl-furfural that cause inhibition of microorganisms and enzymes.