材料期刊网

以青海湖野生菌株Halomonas ventosae QHL5为材料，初步探讨了多种因素对胞内相容溶质四氢嘧啶（ Ectoine）合成的影响．通过设置OSM培养基（ Oesterhelt?Stoeckenius medium）的不同单因素诱导条件（ Na＋、K＋、Mg2＋、pH和温度等），培养 QHL5菌株，并采用80％乙醇抽提 QHL5胞内四氢嘧啶，进行高效液相色谱（HPLC）定量检测．结果表明，QHL5胞内四氢嘧啶积聚的最佳单因素培养条件为Na＋浓度为1．5 mol·L－1，K＋浓度为0．75 mol·L－1，Mg2＋浓度为0．2 mol·L－1，pH 8．0和35℃．在优化条件下，QHL5积聚的四氢嘧啶最大浓度为379．6±8．26 mg·L－1，达到167．1±3．64 mg·g－1细胞干重． QHL5胞内的四氢嘧啶合成受到Na＋的渗透刺激作用，生物量却受到高浓度Na＋的抑制，低浓度Mg2＋（0．1—0．6 mol·L－1）和中浓度的K＋（0．5—1．2 mol·L－1）对四氢嘧啶的生物合成具有重要的渗透刺激作用．与已报道的四氢嘧啶合成菌株相比，QHL5能合成单一的、高浓度的四氢嘧啶，具备潜在的商业制备和应用开发价值．

Wild H. ventosae QHL5 strain,as a research material,was isolated from Qinghai Lake. In order to reveal the relationship between intracellular ectoine accumulation and external environment condition,strain QHL5 was cultured in the improved Oesterhelt?Stoeckenius medium ( OSM) by setting different concentration conditions ( such as Na+,K+,Mg2+,pH and temperature) . Intracellular ectoine was extracted using the 80% ethanol method, and quantitative detection of ectoine was performed using the high performance liquid chromatography ( HPLC) . The results showed that the optimal cultural conditions for ectoine accumulated in the QHL5 were 1.5 mol·L-1 Na+,0.75 mol·L-1 K+,0. 2 mol·L-1 Mg2+, pH of 8. 0, and for 35 ℃. The maximum concentration of ectoine was 379.6 mg·L-1,reaching 167.1 mg·g-1 cell dry weight (CDW). Intracellular ectoine in the QHL5 strain increased with the salinity of sodium ions. However,higher concentrations of Na+inhibited the biomass. Besides,low concentration of Mg2+( 0. 1—0. 6 mol·L-1 ) and moderate concentration of K+(0.5—1. 2 mol·L-1 ) had an important role on stimulating ectoine biosynthesis. Compared with previously reported strains, QHL5 could synthesize higher concentrations of pure ectoine. These preliminary studies may provide certain technical support and be very valuable in the commercial preparation of ectoine.