Dasgupta Debdeep, Ghosh Ritabrata, Sengupta Tapas K
Department of Biological Sciences, Indian Institute of Science Education & Research-Kolkata, Mohanpur Campus, Nadia 741252, India.
ISRN Biotechnol. 2013 Mar 5;2013:250749. doi: 10.5402/2013/250749. eCollection 2013.
The bioavailability of organic contaminants to the degrading bacteria is a major limitation to efficient bioremediation of sites contaminated with hydrophobic pollutants. Such limitation of bioavailability can be overcome by steady-state biofilm-based reactor. The aim of this study was to examine the effect of such multicellular aggregation by naturally existing oil-degrading bacteria on crude oil degradation. Microorganisms, capable of utilizing crude oil as sole carbon source, were isolated from river, estuary and sea-water samples. Biochemical and 16S rDNA analysis of the best degraders of the three sources was found to belong to the Pseudomonas species. Interestingly, one of the isolates was found to be close to Pseudomonas otitidis family which is not reported yet as a degrader of crude oil. Biodegradation of crude oil was estimated by gas chromatography, and biofilm formation near oil-water interface was quantified by confocal laser scanning microscopy. Biofilm supported batches of the isolated Pseudomonas species were able to degrade crude oil much readily and extensively than the planktonic counterparts. Volumetric and topographic analysis revealed that biofilms formed in presence of crude oil accumulate higher biomass with greater thickness compared to the biofilms produced in presence of glucose as sole carbon source.
有机污染物对降解细菌的生物可利用性是高效生物修复受疏水性污染物污染场地的主要限制因素。基于稳态生物膜的反应器可以克服这种生物可利用性的限制。本研究的目的是考察天然存在的石油降解细菌形成的这种多细胞聚集体对原油降解的影响。从河流、河口和海水样本中分离出能够将原油作为唯一碳源利用的微生物。对这三种来源中最佳降解菌的生化分析和16S rDNA分析发现它们属于假单胞菌属。有趣的是，其中一个分离株与耳炎假单胞菌家族关系密切，该家族尚未被报道为原油降解菌。通过气相色谱法估算原油的生物降解率，并用共聚焦激光扫描显微镜对油水界面附近的生物膜形成进行定量分析。与浮游型对应物相比，生物膜支持的分离假单胞菌属批次能够更迅速、更广泛地降解原油。体积和地形分析表明，与以葡萄糖作为唯一碳源产生的生物膜相比，在原油存在下形成的生物膜积累了更高的生物量，厚度更大。
