Isolation, screening and statistical optimizing of L-methioninase production by Chaetomium globosum

Egyptian soil sample was screened for isolation methioninlytic fungi by a rapid plate assay procedure. Eighteen strains of different isolated fungi were screened quantitavely for their L-methioninase activity. Chaetomium globosum was the most efficacious isolate and a dematiaceous filamentous fungi, it was identified at the molecular level by ribotyping 18S rRNA along with the biochemical characterization, and lastly completed by BLAST analysis by structure of a phylogenetic tree. Results showed that, the optimum levels of the incubation period, temperature, pH, methionine, sucrose and sodium nitrate concentrations were 3 days, 30°C, 7, 0%, 30 g/l and 1g/l, respectively. According to the produced model, at these levels, C. globosum produce L-methioninase with predicted specific activity of (≈2225 U/mg); so L-methioninase could be a good source for clinical therapeutic application. The rRNA sequence of C. globosum was deposited to gene bank under accession number KXO24450 Key words: L-methioninase, Chaetomium globosum, 18S rRNA, enzyme optimization, soil.