Ectoine高产菌株Halomonas sp.XH26的鉴定及紫外诱变选育

Identification of high-yielding strain Halomonas sp.XH26 for producing ectoine and UV mutagenesis breeding

通过紫外线诱变小柴旦盐湖盐单胞菌菌株Halomonas sp.XH26,以获得高产Ectoine的突变株,为工程生产Ectoine提供优良的发酵菌源。采用形态学观察、生理生化试验及16S rRNA基因测序分析明确菌株的分类地位。紫外诱变筛选Ectoine产量超过原始菌株2倍以上的正向突变菌株,HPLC测定胞内Ectoine产量,并对突变株进行连续培养,研究Ectoine的产量稳定性。实验结果显示:原始菌株XH26(Ectoine优化产量456.82 mg/L±15.72 mg/L,CDW 0.71 g/g±0.04 g/g),经9轮紫外循环诱变处理后(50 s为最佳诱变时间),获得7株高产Ectoine突变菌,Ectoine产量均大幅提高(约200%)。其中,积聚量最大的菌株HU09-32,产量可达1351.09 mg/L±17.69 mg/L(增幅290%),将7株突变菌连续培养40 d(接种2 d/次),胞内Ectoine产量稳定,生长特性、增殖速度与积聚量明显优于原始菌株XH26,具有很好的发酵生产和工业应用潜力。

In order to provide an excellent source of fermentation bacteria for engineering production of ectoine,Halomonas sp.XH26 from the Xiao Chaidan Saline lake,was mutated by UV radiation to obtain the mutant strain with high yield of ectoine.Morphological observation,physiological and biochemical test and 16 S rRNA gene sequencing were used to determine the classification status of the strain.The positive mutant strain was screened by UV mutagenesis with ectoine yield more than twice that of the original strain,intracellular ectoine production was determined by HPLC,and the mutant strain was subcultured to study the yield stability of ectoine.The experimental results showed that the original strain XH26(optimal yield of ectoine 456.82 mg/L±15.72 mg/L,CDW 0.71 g/g±0.04 g/g)was treated with 9 rounds of UV mutagenesis,and 7 strains with high-yielding mutant ectoine were obtained,and the yield of ectoine was significantly increased(about 200%).Among them,the strain HU09-32 with the largest accumulation amount had a yield up to 1351.09 mg/L±17.69 mg/L(an increase of 290%),and it was continuously subcultured for 40 days(inoculated for 2 days/time).The intracellular ectoine yield was stable,and the growth characteristics,proliferation speed and accumulation amount were significantly better than the original strain XH26,with good fermentation production and industrial application potential.