Lignocellulosic Biorefineries : (Adding Compost Improves the Biogenic Catalysis of Wheat Straw)

The high content of lignocellulose limits the biodegradability of straw for bioenergy production. To counteract this, a thermo-biological pretreatment was applied to improve the utilization of lignocellulosic biomasses for a biorefinery concept. Pretreatments were applied to a comminuted wheat straw (S) containing 30% dry matter (SW). The thermal treatment was carried out using an autoclave (20 min at 121°C; SWa). Afterwards, biological pretreatment was applied by adding green waste compost. Samples were incubated under aerobic (25°C; SKWa_I) and anaerobic (55°C; SKWa_B) conditions for 14 days. Lignocellulose as well as sugars and volatile fatty acids content of samples and methane production were assessed to evaluate the biogenic catalysis of straw. Results reveal a lignocellulosic degradation in all samples. The use of compost assured the growth of cellulose-degrading anaerobic microorganisms under thermophilic conditions. Methane yields ranged between 190 and 317 L/kgvolatile solids. Thermo-biological pretreatment under aerobic conditions increases the methane potential up to 20%. Moreover, the combination of a thermo-biological pretreatment under thermophilic conditions creates a synergistic effect that accelerates the methane production of straw due to the sugars compounds released during the biogenic catalysis. Further studies are needed to link the chemical composition and dynamics of microbial diversity during incubation using molecular biological methods to elucidate the role of microorganisms and to better understand their mechanisms during incubation used in anaerobic digestion.