假单胞茵胞内酶粗提液对藻毒素MCLR的降解

对比研究了假单胞菌M-6及其细胞内外提取液对微囊藻毒素-LR(MCLR)的降解效率.结果表明,细胞外提取液对藻毒素没有降解作用,胞内酶粗提液能在24h内降解MCLR,日均MCLR降解率是纯菌株M-6的4.7倍.进而研究了酶蛋白浓度、底物MCLR浓度、pH值及环境温度对胞内酶粗提液降解藻毒素效率的影响.当MCLR浓度为15.0mg·l~(-1)时,MCLR适宜的酶促降解反应条件为:酶蛋白浓度280mg·l~(-1),温度为30℃,反应pH值为7.0.MCLR液相色谱结构变化图表明,至少有3种酶参与了胞内酶粗提液降解MCLR的分子过程.

ENZYMATIC DEGRADATION OF MICROCYSTIN-LR BY CELL-FREE EXTRACT OF PSEUDOMONAS M-6

The efficiency of MCLR degradation by Pseudomonas M-6 and its intra- and extra-cellular extracts were compared. The extra-cellular extract had no effect on the degradation of MCLR. However the efficiency of MCLR degradation by Pseudomonas M-6 could be enhanced greatly by enzymes in cell-free extract. The degradation of MCLR per day by the enzymes was 4. 7-fold higher than Pseudomonas M-6. The effects of enzyme concentration, MCLR concentration, pH and temperature on the degradation of MCLR by cell-free extract were further studied. The experimental results showed that the best conditions for the removal of MCLR by cell-free extract were 280 mg ·l~(-1) enzyme, pH 7.0 and 30℃ while the initial concentration of MCLR was 15.0 mg·l~(-1). The pathway of MCLR degradation may be due to the catalytic effects of three enzymes.