Microbial and enzymatic improvement of anaerobic digestion of waste biomass

Metabolic activities of different microorganisms (Bacillus subtilis, B. licheniformis and Aspergillus niger) and hydrolytic enzymes (concentrations: 1 to 200 mg enzyme solids g−1 feed) were studied individually and in combinations with respect to H2 and methane production from damaged wheat grains. Bacillus subtilis, B. licheniformis and pre-existing hydrogen producers (control) produced 45 to 64 l H2 kg−1 total solids and subsequently, with the help of added methanogens, 155 to 220 l methane kg−1 total solids could be produced. H2 production from damaged wheat grains could be decreased to 28% or enhanced up to 152% with respect to control, by employing various microbial and enzymatic treatments. Similarly, it has been made possible to vary methane production capacities from as low as 17% to as high as 110% with respect to control.