Oil Degrading Ability and Mechanisms in Oil Degrading Bacterial Groups Isolated from NAKHODKA Oil Spill

从纳霍德卡溢油中分离到5个石油降解菌群（ODB-SG 1 - 5），并对各菌群进行了菌种鉴定和石油降解率测定。[结果与讨论] 1.各组菌种鉴定：根据16 SrRNA基因的DNA序列、BioLog试验和精细结构观察，各组菌种鉴定如下：ODB-SG 1：柄杆菌属和食烷菌属; ODB-SG 2：盐单胞菌属和食烷菌属; ODB-SG 3：德莱亚菌属和食烷菌属; ODB-SG 4：未鉴定; ODB-SG 5：特别是Alcanivorax sp.在所有鉴定的类群中都存在。所有这些细菌均为革兰氏阴性。2.各细菌细胞组成的比较：SDS-PAGE显示，柄杆菌属、盐单胞菌属和食烷菌属细菌的蛋白带型有明显差异， ...更多信息 orax sp.（ODB-SG 1、2、3、5）的亲缘关系相似，但也存在一定的差异。根据这一结果，我们推测，4 Alcanivorax sp.是Alcanivorax sp. 3的不同种或菌株。每种细菌和组的降解率：通过与它们一起孵育的重油的干重变化来检查它们降解油的能力。各组降解率分别为：ODB-SG 1：10.7%，ODB-SG 2：13.1%，ODB-SG 3：15.0%，ODB-SG 4：13.3%，ODB-SG 5：12.4%。食烷菌对稠油的降解效果较好（4.9 ~ 7.8%），而柄杆菌属和盐单胞菌属对稠油的降解效果较差。因此，ODB-SG 1和ODB-SG 2显示出比单独的Alcanivorax sp.更高的降解速率。由此推测柄杆菌属和盐单胞菌属对稠油的降解有促进作用。4.细菌降解油脂的机理：实验观察到食烷菌浓缩培养基对重油的乳化作用，SDS-PAGE电泳结果表明，该菌在浓缩培养基中分泌脂多糖。少

We have isolated 5 oil degrading bacterial groups (ODB-SG1〜5) from NAKHODKA oil spill, and tried to identify their species and to measure their oil degradation rate about all the bacteria which are included in each isolated group. [RESULTS AND DISCUSSION] 1. Identification of species of bacteria in each group: From DNA sequence of the 16SrRNA gene, BioLog test and the observation of fine structures, the species of bacteria in each group were identified as followed, ODB-SG1 : Caulobacter sp. and Alcanivorax sp. ; ODB-SG2 : Halomonas sp. and Alcanivorax sp. ; ODB-SG3 : Deleya sp. and Alcanivorax sp. ; ODB-SG4 : unidentified; ODB-SG5 : unidentified and Alcanivorax sp. Especially, Alcanivorax sp. existed in all identified groups. All of these bacteria were gram-negative. 2. Comparison of the cell composition of each bacterium: SDS-PAGE showed that bacterial protein band pattern were clearly different among Caulobacter sp. , Halomonas sp. , and Alcanivorax sp. The band patterns of 4 Alcaniv … More orax sp. (in ODB-SG1, 2, 3, 5) were similar, but there were some difference. From this result, we speculated that 4 Alcanivorax sp. are distinct species or strains of Alcanivorax sp. 3. Degradation rates of each bacterium and group: Their abilities to degrade oil were examined by the change in the dry weight of the heavy oil with which they were incubated. The degradation rates of each group were as followed, ODB-SG1 : 10.7%, ODB-SG2 : 13.1%, ODB-SG3 : 15.0%% ODB-SG4:13.3%, ODB-SG5 : 12.4%. The Alcanivorax sp. degraded heavyoil well (4.9〜7.8%), but the Caulobacter sp. and the Halomonas sp. were found unable to degrade heavy oil. Thus ODB-SG1 and ODB-SG2 displayed a higher degradation rate than Alcanivorax sp. alone. From these results, we suppose that Caulobacter sp. and Halomonas sp. can help and accelerate the degradation of heavy oil. 4. The mechanisms of oil degradation by bacteria: We have observed the heavy oil was emulsified by the concentrated culture medium of Alcanivorax sp. SDS-PAGE showed that lipopolysaccharides were secreted in the medium. Less