In-vitro degradation of Czapek and molasses amended post-harvest sugarcane residue by lignocellulolytic fungal strains

Abstract

Post-harvest sugarcane residue (SCR), deposited on sugarcane fields after green harvesting, could serve as a substrate for fungal biomass and lignocellulolytic enzymes production. In the present study, the mycelial growth of six strains (Trametes sp. Y–H11, Bjerkandera sp. Y-HHM2, Phanerochaete sp. Y-RN1, Pleurotus sp. Y-RN3, Myrothecium sp. S-3.20 and Hypocrea nigricans SCT-4.4) was measured in-vitro by applying a modified Gompertz equation. In-vitro assays showed shorter lag phases for fungi in modified Czapek, 0.3% and 1.0% molasses amended post-harvest SCR. Further increments in molasses concentrations produced a reduction on the specific growth rates for all tested fungi. Fungal degradation of post-harvest SCR and the concomitant enzyme production were tested under solid-state fermentation (SSF) of Czapek or molasses amended post-harvest SCR. Under SSF, Pleurotus sp. Y-RN3 produced the highest laccase titers but no hydrolytic activity could be detected. Trametes sp. Y–H11 and Myrothecium sp. S-3.20 showed high endoglucanase activities. Endoxylanase production was detected exclusively in Czapek amended media. These findings have implications for the fungal treatment of post-harvest SCR and its potential impact on the use of these residues in the production of biofuels and ligninolytic enzymes.