[Isolation and characterization of a new epsilon-poly-L-lysine-producing strain TUST-2].

OBJECTIVE: Epsilon-Poly-L-Lysine (epsilon-PL) is a natural amino acid homopolymer. The study aimed at isolating new epsilon-PL-producing strains. METHODS: epsilon-PL-producing strains were screened from the soil by using a new isolation approach which had three steps, (1) enrichment culturing epsilon-PL toleranting strains; (2) screening by improved Nishikawa's method; (3) selection of strains with higher epsilon-PL tolerant ability. RESULTS: A new epsilon-PL-producing strain TUST-2 was isolated from the soil collected from Hainan province, China. Chemotaxonomic and morphological characteristics of the isolate were typical of strain of the genus Streptomyces. The strain TUST-2 was found to belong to Streptomyces diastatochromogenes by comparative 16S rRNA gene sequence analysis. The purified fermentation product of the strain TUST-2 was confirmed as epsilon-PL by characteristic analysis, hydrolysate analysis, infrared spectrum, 1H NMR Spectrum, 13C NMR Spectrum, and MALDI-TOF-MS. CONCLUSION: On the basis of 16S rRNA gene sequence analysis and its morphological and physiological characteristics, epsilon-PL-producing strain TUST-2 is a new isolate of Streptomyces diastatochromogenes, named as Streptomyces diastatochromogenes TUST-2.