Producing Enzymes from Molds to Convert Cellulose into Glucose and Alcohol. Final Report

摘要

The following significant results were obtained: (1) extracts of various tree barks were made and used to determine if any of the chemicals had growth stimulating effects on the molds. The extracts from the oak and elm tree bark were very active in inducing and stimulating the mycelial growth of the molds Trichoderma reesei, Pleurotus ostreatus and Aspergillus awamori. Efforts to determine what specific chemical caused the increase in growth were unsuccessful but are being continued. This information will be very useful because it was discovered that by speeding and increasing the growth of the mold cells, it was also possible to speed and increase the production of the enzymes; (2) efforts to cultivate the mold Pleurotus ostreatus in the same culture with Trichoderma reesei were successful. When the two molds were cultured on an enriched cellulose media, it was discovered that the reesei produced large amounts of the beta glucosidase. Reesei produces very small amounts of this enzyme under normal conditions but this high production under coculture conditions may be due to the fact that Pleurotus ostreatus removes the glucose formed from the cellulose breakdown. Trichoderma reesei produces cellulases which convert cellulose into cellobiose and cellobiose is converted to glucose by the enzyme beta-glucosidase. In the presence of glucose the gene producing beta-glucosidase is repressed by the feedback mechanism. These surplus enzymes can then be used for saccharifying cellulose from wastepaper, wood pulp, cornstalks, wheat straw and other cellulosic materials and eventually produce alcohol; (3) efforts to produce mutants of the Trichoderma reesei by using the uv irradiation were unsuccessful; and (4) Zymomonas mobilis is capable of faster fermentation. The only drawback is that only low concentrations of glucose can be used. Mutants of Zymomonas resistant to higher alcohol levels would help in this process and are being looked into. (ERA citation 09:019884)