Valorization of rubber tree sawdust biomass for the production of laccase-lignin peroxidase and bioconversion of sawdust

Rubber tree sawdust was used as a cheap substrate for the production of enzymes in solid-state fermentation (SSF). To enhance enzyme activity and reduce the production cost of enzymes, the simultaneous production of laccase (LaC) and lignin peroxidase (LiP) from Trichoderma homatum strain NGL1 was investigated. Enzyme production was optimized by adapting the design of experiments using response surface methodology. The central composite design was based on 20 experimental runs for the selected three variables (malt extract, glucose, and copper sulfate). LaC activity varied from 14.9 to 159.3 U/gds and LiP ranged between 81 and 464 U/gds. Response surface methodology design improved more than 3-fold LiP and LaC production than unoptimized medium. The optimized medium composition for this strain was 0.64% malt extract, 0.412% glucose, and 0.084 mM copper sulfate. Both LaC and LiP activities were controlled by the designed medium components in the fermentation process. These LaC–LiP enzymes from the fungal strain hydrolyze lignin from the rubber sawdust. Thus, this strategy is used for the conversion of sawdust biomass into fermentable sugar, and subsequent biofuel production could become a useful approach for the commercial production of biofuels.