Present address, Von Einem Str. 25, 48159, Münster, Germany.
Microbiology program, Department of Biological Sciences, Faculty of Science, Kuwait University, P.O. Box 5969, 13060, Safat, Kuwait.
BMC Microbiol. 2019 Feb 18;19(1):41. doi: 10.1186/s12866-019-1406-x.
The group of the so-called obligate hydrocarbonoclastic bacteria (OHCB) are marine microorganisms affiliated with the genera Alcanivorax, Cycloclasticus, Oleiphilus and Thalassolituus. This small group plays a major role in oil-bioremediation in marine ecosystems. Marinobacter and Planomicrobium are considered related to this group. The OHCB are claimed to be obligate to hydrocarbon nutrition. This study argues against this claim.
Four Alcanivorax species, three Marinobacter species and Planomicrobium okeanokoites from the Arabian/Persian Gulf proved to be not obligate to hydrocarbon nutrition. Although the eight strains grew on crude oil, n-octadecane and phenanthrene as sole carbon substrates, their growth was weaker than on certain nonhydrocarbon, organic compounds viz. peptone, glutamic acid, pyruvic acid, sucrose, mannose and others. Glucose and lactose failed to support the growth of seven of the eight tested strains. Mannose was utilized by five and sucrose by six strains. The well-known intermediate metabolite; pyruvic acid was utilized by all the eight strains, and lactic acid by five strains. In batch cultures, all the tested species consumed higher proportions of peptone than of n-alkanes and phenanthrene. When peptone and crude oil were provided together into the medium, the OHCB started to consume peptone first, and the enriched bacterial populations consumed oil effectively. Added nonhydrocarbon substrates biostimulated oil-consumption by all OHCB species.
The tested OHCB species are not obligate hydrocarbon-utilizers. This provides them with the merit of survival, should their marine ecosystems become oil- or hydrocarbon-free. The fact that conventional, organic substrates biostimulated hydrocarbon-consumption by the tested bacterial species confirms the facultative nature of those organisms and is interesting from the practical point of view.
所谓的专性烃类分解菌（OHCB）群体是海洋微生物，隶属于Alcanivorax、Cycloclasticus、Oleiphilus 和 Thalassolituus 属。这一小群微生物在海洋生态系统中的石油生物修复中起着重要作用。Marinobacter 和 Planomicrobium 被认为与该群体有关。据称，OHCB 专性依赖于烃类营养。本研究对这一说法提出质疑。
来自阿拉伯/波斯湾的四种 Alcanivorax 种、三种 Marinobacter 种和 Planomicrobium okeanokoites 被证明不是专性烃类营养。尽管这 8 株菌能够以原油、正十八烷和菲作为唯一的碳源生长，但它们的生长能力弱于某些非烃类有机化合物，如蛋白胨、谷氨酸、丙酮酸、蔗糖、甘露糖等。在测试的 8 株菌中，7 株菌无法利用葡萄糖和乳糖，而 5 株菌可以利用甘露糖，6 株菌可以利用蔗糖。众所周知的中间代谢产物丙酮酸被所有 8 株菌利用，而 5 株菌利用乳酸。在批式培养中，所有测试的种都比烷烃和菲消耗更多的蛋白胨。当将蛋白胨和原油一起添加到培养基中时，OHCB 首先开始消耗蛋白胨，富集的细菌种群有效地消耗油。添加的非烃类底物生物刺激了所有 OHCB 种对油的消耗。
测试的 OHCB 种不是专性烃类利用者。如果它们的海洋生态系统中没有油或烃类，这使它们具有生存的优势。事实上，常规有机底物生物刺激了测试的细菌种对烃类的消耗，这证实了这些生物的兼性性质，从实际角度来看是很有趣的。
