ENHANCED PRODUCTION OF TRICHODERMA CELLULASES THROUGH RECONSTRUCTION OF CELLULASE GENES

Abstract

Trichoderma fungi produce economically important cellulases that comprise three key enzymes; endoglucanases, exoglucanases, and β-glucosidases.  In this study, a total of 28 isolates from Nile Delta were analyzed. The objectives were: 1) species identification of isolates, 2) evaluation of strains' cellulases production in submerged (SmF) and solid state (SSF) fermentation systems, 3) improve strains' cellulases production by mutagenesis and 4) enhance production of strains' cellulases through protoplast fusion and genome shuffling. On the basis of morphological characterization and molecular identification by DNA sequences analysis of ITS region, isolates were identified to species level as strains. 11 strains were chosen because of their unique properties in cellulase screening tests and they were investigated for the production of cellulases in SmF and rice straw SSF cultures. According to detailed examinations of culture filtrates, four promising strains were selected and subjected to genetic improvement through mutagenesis. Nine produced mutants showed better cellulases production than their parents. Moreover, the protoplast fusion of the nine mutants produced stable fusants that showed a marked increase in cellulase production over their mutant parents and original wild-type parents.  Finally, genome shuffling of Trichoderma cells produced strains were higher than their original wild-type parents in cellulase production.