假单胞菌降解微囊藻毒素的效能及酶作用机理

BIODEGRADATION AND BIOMECHANISM OF MICROCYSTIN-LR BY PSEUDOMONADACEAE

以从福州市某富营养化水库底泥中筛选出的假单胞菌M-6为研究对象,分别考察接种量、温度、供氧量(转速)、pH值、微囊藻毒素MCLR初始浓度等条件因素对假单胞菌M-6降解MCLR的影响,并探讨假单胞菌M-6降解MCLR的分子生物学机理。结果表明,当接种量为10%时,菌体的降解效果较好,6d的降解率可达90%;降解反应的最适pH为7.0,最佳温度为30℃,摇床转速控制在150 r/min;MCLR初始浓度过高都将影响假单胞菌M-6对碳源和氮源的吸收和利用,最佳浓度为15.7 mg/L。SDS-PAGE电泳分析表明,假单胞菌M-6降解藻毒素过程中,主要有3种酶参与反应,且这3种酶都是细胞内本身所含有的组织酶。

The high-efficiency microcystin-LR-degrading strain Pseudomonadaceae M-6, which isolated from the sediment of eutrophic reservoir in Fuzhou, China, for the biodegradation of MCLR was investigated. We studied the influence of inoculum concentration, temperature, aeration, pH and initial concentration of MCLR on MCLR degradation by Pseudomonadaceae M-6. It was shown that the biodegradation rates could be reached to 90% at 10% inoeulum concentration, pH 7.0, 30~C , and aeration speed of 150 r/min after 6 days. The MCLR degradation rates were also affected by the initial concentrations of MCLR owing to the effect of the absorption of nitrogen and carbon sources by Pseudornonadaceae M-6. The 6-day biodegradation rate was more than 95% when the initial MCLR concentration was 15.2 mg/L. From SDS electrophoresis, it can be concluded that the MCLR biodegradation was mainly due to the three kinds of enzymes which were all intraeellular enzymes.