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污染控制技术及原理

Diversity and biodegradation characteristics of a halophilic bacterial consortium capable of degrading BETX

摘要：从胜利油田采油井口的盐碱化油污土壤中富集分离出一个高效降解BTEX的嗜盐菌群,通过PCR-DGGE技术和16SrDNA序列分析,确定该菌群主要由海杆菌属(Marinobacter)、盐单胞菌属(Halomonas)、食碱菌属(Alcanivorax),梭菌属(Clostridium)的细菌等组成.在5%盐度的海盐培养基中,该降解菌群可以在56h内将100mg·mL^-1的苯完全降解,在112h内将20～400mg·mL^-1的BTEX混合底物完全降解.进一步的研究结果表明,菌群的盐度适应范围为5%～20%,在pH=6.5～9.5的范围内均可以降解苯,最佳pH=7.5.降解菌群在20～45℃下均可高效降解苯,30℃为最佳降解温度.微量酵母粉(0.01%～0.02%)的添加可以显著提高菌群的降解速率1.3～1.7倍.

Abstract：Abacterial consortium capable of degrading BTEX(benzene,toluene,ethylbenzene and xylene)was developed from oil-contaminated saline soil at 30℃ in 5% sea salt defined medium(SSDM).In 5% SSDM,100 mg·L^-1 benzene could be degraded by the consortium within 56 hours,while 20～400 mg·L^-1 BTEXmixtures could be degraded within 116hours.The biodegradation of benzene by the consortium in 5% SSDMwas evaluated at different temperatures ranging from 4℃ to 60℃ and different pHs ranging from 6.5～9.5.The results indicated that the biodegradation of benzene occurred at a maximum rate of 42.8 μg·mL^-1·d^-1 at 30℃ and pH7.5 with 0.02%(v/v)yeast extract addition.16SrDNAgene analysis revealed that most of the sequences from the DGGE profile of the consortium were related to halophilic genera,such as Marinobacter,Halomonas,and Alcanivorax,already known for their ability to degrade BTEX.Our results suggested that the biodegradation of BTEXby halophilic bacteria is promising for application to hypersaline conditions in the future.