沉水植物轮叶黑藻附生细菌对双酚A的降解能力研究

沉水植物附生细菌可能具有降解转化水体中双酚A（BPA）能力从而影响该污染物在环境中的归趋.以轮叶黑藻为代表，分离筛选其BPA降解附生菌，结果共获得22株，在接种量为1×10⁸个/mL，37℃下72h对BPA的去除率为11.46%~25.06%.选择降解率最高的3株细菌B12、B14和B23，采用16S rDNA鉴定，结合生理生化反应和形态观察，3株细菌分别为属于Lysinibacillus sp.（杆菌属），Brevibacterium sp.（短杆菌属）和Ochrobactrum sp.（苍白杆菌属）.将3株菌株添加至轮叶黑藻无菌苗体系中，发现BPA去除率显著下降（P<0.05）.物理去除部分野生轮叶黑藻表面部分附生细菌后，BPA去除率反而上升（约5%）.综合本研究结果，沉水植物附生细菌具有降解BPA的能力，但在沉水植物-附生生物体系去除BPA过程中贡献较小（约为23%，2d），植物本身起关键作用.

Degradation of bisphenol A by the epiphytic bacteria of submerged macrophytes Hydrilla verticillata (L.f.) Royle

Epiphytic bacteria of submerged macrophytes may have the capability in biodegradation and/or biotransformation of bisphenol A (BPA) in water column, therefore affect the fate of such environmental pollutant. In this research, Hydrilla verticillata (L. f.) Royle was selected and their attached BPA degrading epiphytic bacteria attached were isolated. Among the 22bacteria strains, the BPA removal rates were from 11.46% to 25.06% with the inoculum density at 1×10^-8cell/mL and culture at 37℃ for 72h. The most effective bacteria strains, B12, B14and B23 were identified as Lysinibacillus sp., Brevibacterium sp. and Ochrobactrum sp., respectively, according to the results of 16S rDNA sequencing and morphological, physiological and biochemical tests. But aseptic seedlings of H. verticillata significantly decreased their BPA removal rates after the addition with B12, B14and B23 (P<0.05). Natural seedlings of such species surprisingly increased about 5% in BPA removal after partially removing their epiphyte with physical methods. All the results indicated that epiphytic bacteria of submerged plant can remove BPA, although their contributions (about 23%) are less than the host plants in the submerged macrophytes-epiphyte associations.