Recent advances in methane and hydrogen production from lignocellulosic degradation with anaerobic fungi

Anaerobic fungi (AF) efficiently degrade lignocellulosic biomass with unique pseudoroot system and enzymatic properties that can remove polysaccharides and some lignified components from plant cell walls, further releasing acetate, lactate, ethanol, hydrogen (H-2), etc. As research on AF for bioengineering has become a hot topic, a review of lignocellulosic conversion with AF for methane (CH4) and H-2 production is needed. Efficient degradation of lignocellulose with AF mainly relies on multiple free carbohydrate-active enzymes and cellulosomes in the free and bound state. Meanwhile, co-cultivation of AF and methanogens significantly improves the lignocellulose degradation and CH4 production, and the maximum CH4 yield reached 315 mL/g. Bioaugmentation of AF in anaerobic digestion increases the maximum CH4 yield by 330 %. Also, AF show H-2 production potential, however, H-2 yield from anaerobic fungal fermentation of lignocellulose remains low. Therefore, anaerobic fungi have great potential in the conversion of lignocellulosic biomass to CH4 and H-2.