Performance of wood-rotting fungi-based enzymes on enzymic saccharification of rice straw.

BACKGROUND: For effective saccharification of rice straw we focused on enzyme preparations from wood-rotting fungi that have the ability to degrade cell wall polysaccharides and lignin. We tested extracellular enzyme preparations from 14 species of fungi for saccharification activity and examined the factor for saccharification by statistical analysis. RESULTS: An enzyme preparation from Schizophyllum commune had the highest saccharification activity of rice straw. This preparation contained highly active endo-ß-xylanase, endo-ß-glucanase (CMCase), ß-d-glucosidase and acetylxylan esterase. Correlation analysis of the 14 enzyme preparations demonstrated that acetylxylan esterase was closely related to saccharification activity in rice straw. Multiple regression analysis also showed that acetylxylan esterase had an important role in saccharification. Ligninolytic enzymes, which are characteristic of white-rot fungi, did not contribute to saccharification activity of rice straw. CONCLUSION: Deacetylation is an essential factor for saccharification of rice straw and enzyme preparations for saccharification need to contain highly active acetylxylan esterase as well as highly active cellulolytic and xylanolytic enzymes, but not ligninolytic ones.