Research Article
Ahmed M. El-Bondkly, A. A. M.
Abstract
In an attempt to construct superior Trichoderma harzianum isolates for improvement β-glucosidase productivity, induction of mutants was applied. After application of UV irradiation and Ethyl methane sulfonate (EMS), 461 isolates were obtained, out of them 99 after UV application and 362 isolates after EMS treatments. Five isolates (two after UV application and three after EMS treatments) were selected on the basis of their highly productivity of both enzymes to be treated with doses of colchicine (0.1% and 0.2%) as a second step of induction mutation. After colchicine treatments, 191 isolates were obtained, out of them 40 isolates after treating the wild type strain, 70 isolates after treating the two UV induced-mutants with colchicine and 81 isolates after treating the three EMS induced-mutants with colchicine .These isolates were tested for their CMCase and β-glucosidase productivities. One isolate (D1/4) proved to be the highest producer for the two enzymes, since it produced 160% and 186% CMCase and β-glucosidase, respectively, more than the original strain. In addition, highest DNA content and also highest amounts of CMCase and β-glucosidase were obtained after EMS-treatments followed by colchicine application.