Isolation cellulase mutants, screening

Selective Screening Methods for the Isolation of High Yielding Cellulase Mutants of Trichoderma reesei... 

Montenecourt and Eveleigh (37), using a special agar screening technique, have also isolated a cellulase enhanced mutant (NG-14). They suggest, however, that the cellobiohydrolase and the endoglucanase biosynthesis are regulated by different controls. They base this assumption on data for the relative ratios of cellulases obtained from this mutant needed to hydrolyze different substrates. 

A number of selective-screening methodologies have been devised that have allowed isolation of a series of hyperproducing and catabolite repression-resistant mutants of T. reesei. Yields of cellulase of 15 units/ mL under controlled fermentor conditions have been achieved with both Rut-NG14 and Rut-C30. Quantitative reaction of Rut-NG14 enzyme preparation with purified antibodies to cellobiohydrolase shows that in this mutant, the cellobiohydrolase is specifically hyperproduced relative to the rest of the enzymes in the cellulase complex. Rut-C30, which was derived from Rut-NG14, shows resistance to catabolite repression for... 

The development of an agar plate screening technique has allowed the isolation of a range of mutants of Trichoderma reesei capable of biosynthesizing cellulase under conditions of high catabolite repression. Commercial aspects of the production and isolation of hyper-cellulase-producing mutants of T. reesei were discussed. 

---