转谷氨酰胺酶高产菌株的选育及发酵条件优化

Breeding of producing transglutaminase strains and optimizing fermentation conditions

以茂原链霉菌作为出发菌株,对其进行紫外线诱变育种,诱变时间为50s,通过摇瓶液体发酵进行筛选,获得一株产转谷氨酰胺酶能力高的变异菌株MY78,与出发菌株(转谷氨酰胺酶酶活力为0.25U/mL)相比,其转谷氨酰胺酶的酶活力提高了2.28倍,突变株遗传性能稳定。以转谷氨酰胺酶活力和菌体细胞生长量作为指标,对其发酵条件进行研究。结果表明,最适发酵条件:培养基初始pH值为7.0,培养时间为54h,培养温度为30℃,接种量为10%(V/V),摇床转速为200r/min。在该条件下进行发酵,微生物产转谷氨酰胺酶活力达到(1.15±0.09)U/mL,菌体生物量可达(6.32±0.01)g/L。

Streptomyces mobaraensis was used as the original strain. The strain was mutated with ultraviolet, and the mutation time was determined as 50 s. A mutant strain MY78 with the higher capacity for enzymatic production was obtained. Compared with the original strain （transglutaminase activity was 0.25 U/mL）, the transglutaminase activity produced by the mutant strain increased 2. 28 times. The mutant strain had genetic stability. The mutant strain was used to ferment to prepare transglutaminase by shake flask. The optimized fermentation conditions were as followed., initial pH 7.0,inoeulum size 10% （V/V）, temperature 30℃, shaking speed 200 r/rain, and fermentation time 54 h. In the conditions, the transglutaminase activity and biomass of the strain were （1.15 ±0. 09） U/mL and （6.32 ±0. 01） g/L, respectively.