大肠杆菌SOD高产菌的诱变选育及产酶条件优化

Mutation Breeding of High Producing Strain of Superoxide Dismutase from Escherichia Coli and Optimization of the Culture Conditions

以大肠杆菌为出发菌株,通过紫外线诱变处理,选育出一株SOD高产菌株(编号为ECM3).其SOD酶活达4 098.1 U/g,为实验出发菌株的2.1倍.经连续传代5次后仍稳定产酶.同时还对该目的菌株的产酶条件进行了优化,其最佳产酶条件为:250 mL三角瓶装液量60 mL,接种量2.5%(体积分数),培养基起始pH值为7.2,培养温度37℃,时间16 h.在此条件下,SOD酶活力为4 435.5 U/g.

The strain of Escherichia coli was selected as the original strain.Treated with UV mutagenesis,a high-producing mutant（designated as ECM3）was obtained.The enzyme activity of SOD reached 4 098.1 U/g fresh cells,which was 2.1 times of the original strains.The mutant was transferred for 5 times and its enzyme activity of SOD was stable.And the fermentation conditions for the SOD enzyme production of the Escherichia coli were examined.The results showed that the optimal shake-flask cultivation condition was as follows：the liquid content was 60 mL in a 250 mL Erlenmeyer flask,the inoculation content was 2.5 %（volume fraction）,the initial pH was 7.2,the temperature was 37 ℃ and culture time was 16 hours.In this condition,the SOD activity was 4 435.5 U/g fresh cells.