琼胶降解菌产酶条件优化、酶学性质和糖代谢途径

    Optimization of fermentation conditions, enzymatic properties and sugar metabolic pathways of agarase-producing strain

    • 摘要: 为确定热带海洋环境中琼胶降解菌的最佳产酶条件和最适培养条件,提高其产酶能力,采用3,5-二硝基水杨酸(3,5-Dinitrosalicylic acid,DNS)比色法测酶活,研究其酶学性质并利用高通量测序获得其参加糖代谢的酶。单因素和多因素研究结果表明院FG12 的最佳产酶条件为1%蛋白胨、0.8%琼脂、0.02% K2HPO4、pH 7.5、28益;最适培养条件为0.8%琼脂粉、0.5%蛋白胨、pH 6.8。优化后的酶活达到739.58 U/mL,比优化前提高了273.49%。琼胶酶的最适温度为36益,在36~55益之间的热稳定性很好;最适pH 值为7.5,在pH 为6.5~7.5 时,酸碱稳定性较好。高通量测序的代谢图中,FG12 中含有多种不同数量的酶参与糖代谢,能通过基因改造提高酶产量。因此,FG12 是一株高效琼胶降解菌,为潜在的工程菌。

       

      Abstract: To determine the optimal fermentation conditions and culture conditions of FG12, an agarase-producing strain was taken from the tropical marine environment for improving its enzyme activity, 3,5-Dinitrosalicylic acid (DNS) method was used to determine the enzyme activity and study its enzymatic properties, and the high-throughput sequencing was applied to obtain enzymes involved in glucose metabolism. By the test of single factors and multiple factor, the optimal agarase-producing medium was as follows: 0.8% agar, 1% peptone, 0.02% K2HPO4, 28 and pH 7.5; the optimal culture medium was as follows: 0.8% agar, 0.5% peptone and pH 6.8. The activity reached the highest value of 739.58 U/mL which was 273.49% times higher than that under the original conditions. Enzymatic properties showed that its optimal temperature and pH were 36 and 7.5, respectively, it was stable at 36~55 and pH 6.5~7.5. Analysis on KEGG metabolism pathways showed that a variety of different enzymes from FG12 were involved in glucose metabolism, which could improve the enzyme production through genetic modification. The results indicate that FG12, an efficient agarase-producing strain, might act as a potential candidate for the industrial application.