Isolation and indentification of Trichosporon asahii from Kimchi and medium optimization in submerge fermentation

Kimchi is a fermented herbal supplement, and appetizer that according to a raw material, process and geographical location are classified more than161 types. In this study, after kimchi production, isolation and identification of microorganisms was performed by molecular method. Lipase producing strain, Trichosporon asahii was isolated from kimchi sample (19.01 ±3 U/ml). The various medium components and culture parameters to achieve a more cost effective and economically viable bioprocess were screened and optimized using Design Expert software. PBdesignsare used to screen the most effective variables on lipase production that fermentation temperature and initial pHfor 48 hours 30 . According to the results, extract of nigella sativa, olive oil, yeast extract, magnesium chloride, respectively, were the most variable. Variable particle size and pepton ehavenegative effect. The variable selection and optimization on was performed more efficiently. Finally, lipase activity was 35 ± 0.5 U/ml in the optimal conditions using a medium containing15% sativa extract, 10 g/l yeast extract, 22.5 g/l olive oiland25 mM/l magnesium chloride in the rotation speed of 150 rpm, respectively, as well as enzyme activityafter84/1times the optimal state before optimization. The kinetic parameters V (max) and K (m) was 0.367 mM / min and 0.53 mM through Michaelis–Menten Chart, respectively. Low K_m indicates high affinity between enzyme and substrate and high V_max demonstrates high catalytic performance of the enzyme