一株荧蒽降解菌Herbaspirillum chlorophenolicum strain FA1的固定化及其优化

对草螺菌属荧蒽降解菌Herbaspirillum chlorophenolicum strain FA1以不同材料和方法进行固定化,考察固定化后菌株对土水系统中荧蒽的降解性能。结果表明:聚乙烯醇(PVA)-硅藻土载体(硼酸法)固定的菌株对荧蒽的降解效率最高,对荧蒽的25-d降解率达97.74%;硼酸法制备的PVA-硅藻土载体和PVA-活性炭载体对荧蒽的降解效果优于相应冷冻-解冻法制得的载体;硅藻土的添加比活性炭更能够提高固定在PVA复合载体中的菌株FA1对荧蒽的降解率。在此基础上,对PVA-硅藻土载体(硼酸法)进行响应曲面法优化,采用4水平的Box-Behnken设计安排实验,对结果进行拟合和分析,建立二次回归模型并求解,获得最佳固定化条件为:菌浓度9.6%、PVA浓度11.2%、硅藻土浓度4.5%、粒径4 mm。据此优化后,PVA-硅藻土载体(硼酸法)对荧蒽的20-d降解率即达99.46%。

Immobilization of Fluoranthene-Degrading Herbaspirillum chlorophenolicum strain FA1 and Its Optimization

Microbial remediation of polycyclic aromatic hydrocarbons(PAHs), a group of persistent toxic contaminants that are widespread in terrestrial and aquatic environments, has received increasing interests. A fluoranthene-degrading strain FA1 previously isolated from activated sludge has showed capability to use fluoranthene as sole carbon and energy sources and to degrade fluoranthene in the presence of indigenous flora. In this study, immobilization of fluoranthene-degrading strain FA1 by various matrices and its effects on fluoranthene degradation in soil-water system were investigated. Results showed that the strain FA1 immobilized on polyvinyl alcohol(PVA)-diatomite matrix prepared by chemical method(boric acid) exhibited the highest degradation of fluoranthene, with a 97.74% removal of fluoranthene from soil-water system after 25 d. PVA-diatomite and PVA-activated carbon matrices obtained by chemical method showed better effectiveness than those obtained by freezing and thawing method. The optimal immobilization conditions of PVA-diatomite matrix(chemical method) were 9.6% of cell density, 11.2% of PVA, 4.5% of diatomite and 4.0 mm of bead size. Under these conditions, 99.46% of fluoranthene was removed from the soil-water system after 20 d.