In contrast to (thermo)chemical pretreatments, the use of microbial degradation of lignin to increase feedstock digestibility has several advantages:19

• Energy inputs are low.

• Hardware demands are modest.

• No environmentally damaging waste products are generated.

• Hazardous chemicals and conditions are avoided.

All of these features have associated economic cost savings. Against this, the need for lengthy pretreatment times and the degradation of polysaccharides (thus reduc­ing the total fermentable substrate) have acted to keep interest in biological pre­processing of lignocellulosic materials firmly in the laboratory. A careful choice of organism (usually a wood-rotting fungus) or a mixture of suitable organisms can, however, ensure a high degree of specificity of lignin removal.4748 Extrapolations of this approach could involve either the preprocessing of in situ agricultural areas for local production facilities or the sequential use of the biomass feedstock first as a substrate for edible mushroom production before further use of the partially depleted material by enzymic hydrolysis to liberate sugars from polysaccharides.