Xylanase and cellulase production by Acidothermus cellulolyticus grown on switchgrass in solid-state fermentation

Background: The thermotolerance of Acidothermus cellulolyticus and its wide range of secreted enzymes make this bacterium a promising candidate for industrial biotechnology. Identifying solid-fermentation management strategies to promote the growth of A. cellulolyticus and consequently increase its enzyme generation have not previously been investigated. Results: The addition of nitrogen and buffer did not significantly affect the respiration rate and enzyme activity yield from extracted solids. However, the presence of phenolic monomers reduced A. cellulolyticus growth and enzyme activity yield. Diafiltration of extracts and intermediate leaching were effective approaches for removing the inhibitors and increasing enzyme activity. Conclusions: Enzyme production during solid-state fermentation of A. cellulolyticus, although promising, was negatively affected by phenolic monomers present in switchgrass, which probably masked the effects of other variables tested.