废弃菌体水解液作氮源发酵产腈水合酶的研究

工业生产中微生物细胞在发酵结束后常被作为废弃物丢弃,容易造成环境污染和资源浪费.对废弃细胞进行破壁处理,废弃菌体水解液可替代酵母膏作有机氮源用于发酵产腈水合酶.通过采用超声波、冻融、热碱3种方法破碎细胞,测定水解液中氨基氮含量的高低,确定选择热碱法为最佳细胞破碎方法.通过正交实验选出最优破壁条件为:N aOH加入量5g.L-1,水解温度100℃,水解时间1.5h.在最佳破壁条件下,细胞破碎液中氨基氮含量为24.5 g· L-1.并考察了酵母膏与水解液的不同配比对腈水合酶发酵酶活的影响,确定了酵母膏与废弃菌体水解液的最佳配比为3:2.实验结果表明:利用热碱法处理废弃菌体的水解液作为氮源部分代替酵母膏,发酵酶活为1 063万U·mL-1,而完全利用酵母膏作为氮源的发酵酶活为1 055万U·mL-1.

The Research on the Fermentation Production of Nitrile Hydratase by Using Waste Cell Solution as Nitrogen Source

The waste cells in fermentative production were often discarded directly,causing environmental pollution and the waste of resources.Nitrogen source in the waste cell solution can be reused in the production of nitrile hydratase instead of yeast extract when the cell wall was destroyed.Ultrasonic,freezing and thawing,and hot alkaline were investigated for cell wall-breaking.The results showed that hot alkaline was more effective for higher amino nitrogen content.The optimum reaction conditions were NaOH 5 g·L,100 ℃,1.5 h,which is elected by orthogonal experiment,then the amino nitrogen concentration reached 24.5 g· L.The suitable ratio(3:2)was determined through its impact on the nitrile hydratase activity by using waste cell solution replaced a certain amount of yeast extract as nitrogen source.Compared with the original medium's enzyme activity 1.055×10 U·mL whose nitrogen source was complete yeast extract,the nitrile hydratase activity was 1.063×10 U·mL in the medium containing waste cell solution.