氧化还原介体催化强化Shewanella oneidensis MR-1还原亚硒酸盐的研究

Characteristics of selenite bioreduction by Shewanella oneidensis MR-1 with redox mediators

针对微生物还原亚硒酸盐过程普遍存在的时间较长的问题,考察了4种水溶性醌类介体(α-AQS,AQS,1,5-AQDS和AQDS)对奥奈达希瓦氏菌(Shewanella oneidensis MR-1)还原亚硒酸盐过程的加速作用,通过单因素试验优化了培养条件,对硒纳米颗粒的Zeta电位和粒径进行了表征。结果表明,4种醌类介体都加速了亚硒酸盐的还原,其中,AQDS的加速效果最显著;在pH值为8.0,温度为30℃,AQDS浓度为0.2mmol/L条件下,48h时亚硒酸盐的转化率达到100%;加入AQDS后会生成更大尺寸的硒纳米颗粒,并可能使硒纳米颗粒表面包裹的有机物质成分及含量发生改变。研究结果为Shewanella oneidensis MR-1修复亚硒酸盐污染的实际应用提供了理论依据。

Accelerating the selenite reduction rate is important in selenite bioreduction by microorganism process.This studyinvestigates the impact of redox mediators(α-AQS,AQS,1,5-AQDS and AQDS)on bioreduction of selenite by Shewanella oneidensis MR-1 and optimizes the bioreduction conditions with Shewanella oneidensis MR-1 and AQDS.The selenium particles obtained from cultures are analyzed using Zeta potential analyzer.The results suggest that all four tested redox mediators are able to accelerate the reduction of selenite by Shewanella oneidensis MR-1,and AQDS is the best.The optimum conditons are AQDS concentration of 0.2 mmol/L pH of 8.0 and temperature of 30 ℃.Selenite is completely removed after 48 h bioreduction by Shewanella oneidensis MR-1 with optimum conditons.Bigger size selenium nanoparticles(SeNPS)can be obtained with AQDS.AQDS may influence the composition and content of the organic layer covering around selenium nanoparticles(SeNPs).This study could provide a foundation for particle application in selenite biodegradation.