IRD, UMR-D180 Microbiologie et Biotechnologie des Environnements Chauds, ESIL Case 925, Marseille Cedex 9, France.
J Appl Microbiol. 2010 Jun;108(6):1903-16. doi: 10.1111/j.1365-2672.2009.04592.x. Epub 2009 Oct 20.
To investigate the alkane-hydroxylating system of isolate SP2B, closely related to Rhodococcus ruber DSM 43338(T) and uncharacterized so far for its alkane degradation genes.
Although isolate SP2B and reference strain can grow on by-products from hexane degradation, the type strain R. ruber was unable, unlike SP2B isolate, to use short-chain alkanes, as assessed by gas chromatography. Using PCR with specific or degenerated primers, inverse PCR and Southern blot, two alkane hydroxylase encoding genes (alkB) were detected in both bacteria, which is in agreement with their alkane range. The first AlkB was related to Rhodococcus AlkB7 enzymes and contains a nonbulky residue at a specific position, suggesting it might be involved in medium- and long-chain alkane oxidation. The second partial alkB gene potentially belongs to alkB5-type, which was found in bacteria unable to use hexane. Moreover, a partial P450 cytochrome alkane hydroxylase, thought to be responsible for the hexane degradation, was detected only in the isolated strain.
Rhodococcus ruber SP2B should prove to be a promising candidate for bioremediation studies of contaminated sites because of its large degradation range of alkanes.
This is the first thorough study on R.ruber alkane degradation systems.
研究与红球菌（Rhodococcus ruber）DSM 43338(T)密切相关的分离株 SP2B 的烷烃羟化系统，该系统迄今尚未对其烷烃降解基因进行特征描述。
尽管分离株 SP2B 和参考菌株可以利用己烷降解的副产物生长，但不同于 SP2B 分离株，模式菌株红球菌（R. ruber）不能利用短链烷烃，这可以通过气相色谱法进行评估。使用特异性或简并引物的 PCR、反向 PCR 和 Southern blot，在两种细菌中均检测到两个烷烃羟化酶编码基因（alkB），这与它们的烷烃范围一致。第一个 AlkB 与 Rhodococcus AlkB7 酶有关，并且在特定位置含有非庞大残基，表明它可能参与中链和长链烷烃的氧化。第二个部分 alkB 基因可能属于 alkB5 型，在不能使用己烷的细菌中发现。此外，仅在分离株中检测到部分 P450 细胞色素烷烃羟化酶，该酶被认为负责己烷的降解。
由于其广泛的烷烃降解范围，红球菌（R. ruber）SP2B 有望成为污染场地生物修复研究的有前途的候选菌株。
这是对红球菌烷烃降解系统的首次全面研究。
