Ion Beam Implantation Of Transglutaminase Producing Strain

Low energy N⁺ ion beam implanting was used to mutagenize Steptoverticillum K21 for screening high yield mutant. One of mutants, the strain S2 showed high preference to produce transglutaminase. The transglutaminase activity of S2 was 3.6U/mL and was more 50% than that of the K21. The result of genetic stability experiment of 7 generations showed that strain S2 produce enzyme activity from 94% to 103%. A new and effective pre-screening method, the experiment of casein flocculation precipitation reaction was set up to screen the strain S2. The optimal mutagenic dose 5×10¹⁶ions/cm² was confirmed by reviewing 8 dose , energy 30kev mutagenic effectiveness. The orthogonality experiment was used to optimize cultural conditions, and the result showed that the optimal cultural conditions were pH6.0, temperature 33℃, K₂HPO₄ 0.2%, yeast cream 0.1%, MgSO₄ 0.2%, peptone 2.5%, dissolubility starch 2.5%. The enzyme activity of strain S2 improved 12% under the optimal cultural conditions. The carbon source assimilation experiment showed that the strain S2 assimilated dissolubility starch, fructose, glucose, saccharose, glycerin, mannitol, maltose, didn't assimilate citric acid, and assimilated galactose weakly.