Hypercellulolytic Mutants and Their Role in Saccharification

摘要

The overall objective of this project is to reduce the manufacturing cost of cellulase production. Three goals were set and each has been partially achieved. Firstly, the yields of cellulase from T. reesei have been increased substantially. This has been achieved through the design of selective screening methodologies which have allowed the selection of hyperproducing cellulase mutants. The geneology of the Trichoderma mutants isolated to date utilizing these screening methods is summarized. The yields of cellulase from mutants Rut-NG-14 and Rut-C30 grown in the fermentor are fifteen fold greater than that obtained from the wild strain QM 6a in flask culture. Secondly, several catabolite repression resistant strains (e.g. Rut-C30) have been selected allowing the use of inexpensive culture medium components such as corn steep liquor, without reduction in cellulase yield. A substantial savings in operational cost can be achieved by the use of such strains. Thirdly, thermotolerant strains were considered economically attractive since they reduce the cost of fermentor equipment and operation. Such strains (Rut-C30T) have been isolated from T. reesei that grow well at 37 exp 0 C but to date none show the hypercellulase yields of their parent strains. (ERA citation 04:024621)