Abstract Description

The disposal of unused plant-based biomass contributes significantly to environmental pollution. Recently, such biomass has attracted increasing attention in the biofuel industry as a low-cost raw material. Beyond serving as feedstock, it can also act as a carbon source for producing hydrolytic enzymes required to release fermentable sugars from lignocellulose. Enzymatic conversion is the preferred method for converting plant residues into valuable products, yet high enzyme production costs hinder large-scale application. Using biomass both as substrate and enzyme inducer offers a cost-effective solution, making biofuel production more economically feasible. This study evaluated thatch grass as a carbon source for the production of xylanase and endoglucanase enzymes under submerged and solid-state fermentation and further assessed its potential as a biomass for bioethanol production. Twelve filamentous fungi isolated from the gut of Pachylomerus femoralis, Anachalcos convexus, and Euoniticellus intermedius were screened for xylanase activity. These isolates, belonging to Aspergillus, Trichoderma, Hypocrea, Neosartorya, Talaromyces, Penicillium, and Rhizopus, were selected for their previously demonstrated xylanolytic potential. Pretreatment methods (acid and ammonium solution), fermentation modes (submerged vs. solid-state) and initial moisture content (for solid-state fermentation) were evaluated. Hypocrea lixii AB2A3, Aspergillus fumigatus L1XYL9, and Neosartorya sp. AB2XYL20 were identified as the top xylanase producers, with activities of 525, 304, and 549 nkat/ml, respectively.  Enzymatic saccharification of acid-pretreated thatch grass using crude xylanase from H. lixii AB2A3 yielded 128 mg/g xylose after 72 hours (59 % efficiency). Supplementation of this crude xylanase with Celluclast™ resulted in maximum glucose production of 549 mg/g (60 % efficiency), compared to 528 mg/g (54 % efficiency) when Celluclast™ was used alone. Thatch grass shows strong potential as both an inducer for fungal enzyme production and a substrate for enzymatic saccharification. Instead of being burned and contributing to environmental pollution, it can be valorized to produce industrially important enzymes such as xylanase, thereby lowering costs and improving the efficiency of biofuel production.