Mehboob Farrakh, Junca Howard, Schraa Gosse, Stams Alfons J M
Wageningen University, The Netherlands.
Appl Microbiol Biotechnol. 2009 Jun;83(4):739-47. doi: 10.1007/s00253-009-1985-9. Epub 2009 Apr 8.
Microbial (per)chlorate reduction is a unique process in which molecular oxygen is formed during the dismutation of chlorite. The oxygen thus formed may be used to degrade hydrocarbons by means of oxygenases under seemingly anoxic conditions. Up to now, no bacterium has been described that grows on aliphatic hydrocarbons with chlorate. Here, we report that Pseudomonas chloritidismutans AW-1(T) grows on n-alkanes (ranging from C7 until C12) with chlorate as electron acceptor. Strain AW-1(T) also grows on the intermediates of the presumed n-alkane degradation pathway. The specific growth rates on n-decane and chlorate and n-decane and oxygen were 0.5 +/- 0.1 and 0.4 +/- 0.02 day(-1), respectively. The key enzymes chlorate reductase and chlorite dismutase were assayed and found to be present. The oxygen-dependent alkane oxidation was demonstrated in whole-cell suspensions. The strain degrades n-alkanes with oxygen and chlorate but not with nitrate, thus suggesting that the strain employs oxygenase-dependent pathways for the breakdown of n-alkanes.
微生物（过）氯酸盐还原是一个独特的过程，在此过程中，亚氯酸盐歧化会生成分子氧。如此形成的氧气可在看似缺氧的条件下通过加氧酶用于降解碳氢化合物。到目前为止，尚未描述有能利用氯酸盐以脂肪族碳氢化合物为生长底物的细菌。在此，我们报告嗜亚氯酸盐假单胞菌AW-1(T)能利用氯酸盐作为电子受体，以正构烷烃（碳链长度从C7到C12）为生长底物。菌株AW-1(T)也能在假定的正构烷烃降解途径的中间产物上生长。以正癸烷和氯酸盐以及正癸烷和氧气为底物时的比生长速率分别为0.5±0.1和0.4±0.02天-1。对关键酶氯酸盐还原酶和亚氯酸盐歧化酶进行了测定，发现它们均存在。在全细胞悬液中证实了氧气依赖的烷烃氧化作用。该菌株能利用氧气和氯酸盐降解正构烷烃，但不能利用硝酸盐，因此表明该菌株采用依赖加氧酶的途径来分解正构烷烃。
