海洋真菌厌氧降解PCB180的初步研究

Preliminary research on the anaerobic degradation of PCB180 by marine fungi

利用胶州湾表层沉积物中分离的HTTD-Z0901等4株优势海洋半知菌（标记为LC1、LC2、LC3和LC4）,经富集培养后接种,进行2,2＇,3,4,4＇,5,5＇-七氯联苯（2,2＇,3,4,4＇,5,5＇-Heptachlor biphenyl,PCB180）的移除和诱导后真菌生物膜变化的研究试验。测试结果表明,消除吸附作用贡献后,4株真菌对PCB180的厌氧降解率为2.04%～75.63%;在1～15 d范围内,降解率随着培养时间的增加呈先增大后平稳的趋势;整体上4株真菌的降解效率为LC3〉LC4〉LC2〉LC1。其中,LC3、LC4对PCB180的厌氧降解率在降解10 d时达到最高值,分别为75.63%和49.34%;LC1和LC2对PCB180的厌氧降解率在降解7 d时达到最高值,分别为8.27%和19.15%;不同的真菌对PCB180的厌氧降解率差别较大,LC3菌株对PCB180的厌氧降解率可以达到75.63%,LC1菌株最大只有8.27%。原子力显微镜（Atomic Force Microscope,AFM）观察发现不同真菌的分生孢子会出现不同的变化,如孢子聚合程度增加、孢子形状变化以及原有的标志性特征的消失等。这些结果表明经PCB180诱导的真菌生物膜受到一定程度的破坏,这可能是真菌依靠生物膜对抗PCB180胁迫而产生的自我防护的直观表现。

Four dominant marine imperfect fungi of HTTD-Z0901 ~ HTTD-Z0904（ labeled as LC1、LC2、LC3 and LC4） were isolated from the sediment in Jiaozhou Bay. After enrichment and cultivation,their capability of PCB180 removal was tested. Effect of PCB180 on the fungi biofilm was also studied. Results indicated that the anaerobic degradation rates of PCB180 by the four dominant marine imperfect fungi ranged between 2. 04% ~ 75. 63%. Within 1 to 15 days,the anaerobic degradation rate increased with the incubation time before leveling off. The overall degradation rate follows the trend of LC3〉 LC4〉 LC2〉 LC1. Anaerobic degradation rates of PCB180 by LC3 and LC4 were the highest on day 10 with a rate of 75. 63% and 49. 34% respectively. Whereas the highest degradation rates by LC1 and LC2 were on day 7,which are 8. 27 % and 19. 15 % respectively. We also found that different fungi showed varyingPCB180 anaerobic degradation rates with LC3 a rate of 75. 63% and LC1 a rate of only 8. 27%. AFM results showed that fungal conidium had different changes. These changes included the change of spore shape,the lost of original feature,the lost of the characteristic ring structures,and so on. These morphology changes indicated that,to some extent,the fungal biofilms were damaged after the induction of PCB180. These could be the visual evidence of biofilm dependent self protection against PCB180 by the fungi.