Isolation, identification of a protease-producing endophytic bacteria and its culture conditions
CHU Yanliang;LIU Yujia;YAO Ting;HE Zhongqiong;LU Bo;WANG Yiyuan;College of Biotechnology, Jiangsu University of Science and Technology;
The endophytic strain FFR3 of a high-yield protease was isolated from the root of Radix Saposhnikoviae by gelatin plate screening method. Combined with physiological and biochemical characteristics and 16 S rDNA sequence analysis, the strain was identified as Paenibacillus sp. The enzyme culture conditions of endophytic bacteria FFR-3 were studied by using extracellular protease activity as an index. The results showed that 5 g/L glucose and 7.5 g/L yeast extract were the suitable carbon and nitrogen sources for the growth of the strain. The concentration of MgSO_4·7 H_2O, KH_2PO_4 and FeSO_4·7 H_2O are 3, 5 and 0.1 g/L, which is beneficial to the production of protease. The culture conditions for liquid fermentation were 2% inoculation amount, 50 mL/250 mL, pH 7.0, speed 180 r/m and temperature 37 ℃. After fermented for 48 h with these conditions, the protease activity can reach 633.19 U/mL, which was 15.9 times higher than the primary screening of enzyme activity.