Screening and identification of a Streptomyces platensis YK-2, a new transglutaminase producer

A bacterial strain, YK-2, was isolated as a producer of transglutaminase from a forest soil sample of Daegu, Korea. The isolate showed a G+C content of 72.7 mol%, contained meso-A₂pm as the cell-wall amino acid, and possessed menaquinone MK-9 (H₆) and menaquinone MK-9 (H₈) at a ratio of 6:4. The chemotaxonomic analysis, as well as phylogenetic analysis based on the 16S rDNA sequence, identified the isolate as a member of Streptomyces platensis. For transglutaminase production, the optimum medium composition was determined to be 2% glucose, 1% polypeptone, 1% soytone, and 0.1% MnCl₂. The transglutaminase was stable within the pH range of 5.0-9.0 and 30-45°C, and the optimum pH and temperature were pH 8.0 and 45°C, respectively, without any requirement for Ca²⁺.