Chongcharoen Rotsaman, Smith Thomas J, Flint Kenneth P, Dalton Howard
Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK.
Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield S1 1WB, UK.
Microbiology (Reading). 2005 Aug;151(Pt 8):2615-2622. doi: 10.1099/mic.0.27912-0.
Formaldehyde is a highly toxic chemical common in industrial effluents, and it is also an intermediate in bacterial metabolism of one-carbon growth substrates, although its role as a bacterial growth substrate per se has not been extensively reported. This study investigated two highly formaldehyde-resistant formaldehyde utilizers, strains BIP and ROS1; the former strain has been used for industrial remediation of formaldehyde-containing effluents. The two strains were shown by means of 16S rRNA characterization to be closely related members of the genus Methylobacterium. Both strains were able to use formaldehyde, methanol and a range of multicarbon compounds as their principal growth substrate. Growth on formaldehyde was possible up to a concentration of at least 58 mM, and survival at up to 100 mM was possible after stepwise acclimatization by growth at increasing concentrations of formaldehyde. At such high concentrations of formaldehyde, the cultures underwent a period of formaldehyde removal without growth before the formaldehyde concentration fell below 60 mM, and growth could resume. Two-dimensional electrophoresis and MS characterization of formaldehyde-induced proteins in strain BIP revealed that the pathways of formaldehyde metabolism, and adaptations to methylotrophic growth, were very similar to those seen in the well-characterized methanol-utilizing methylotroph Methylobacterium extorquens AM1. Thus, it appears that many of the changes in protein expression that allow strain BIP to grow using high formaldehyde concentrations are associated with expression of the same enzymes used by M. extorquens AM1 to process formaldehyde as a metabolic intermediate during growth on methanol.
甲醛是工业废水中常见的一种剧毒化学物质，它也是细菌在利用一碳生长底物进行代谢过程中的一种中间产物，尽管其作为细菌生长底物本身的作用尚未得到广泛报道。本研究调查了两株对甲醛具有高度抗性的甲醛利用菌，即BIP菌株和ROS1菌株；前一种菌株已用于含甲醛废水的工业修复。通过16S rRNA特征分析表明，这两株菌是甲基杆菌属的密切相关成员。两株菌都能够利用甲醛、甲醇和一系列多碳化合物作为其主要生长底物。在甲醛浓度至少达到58 mM时仍可生长，通过在逐渐增加的甲醛浓度下生长进行逐步驯化后，在高达100 mM的浓度下也可存活。在如此高浓度的甲醛条件下，培养物在甲醛浓度降至60 mM以下之前会经历一段无生长但去除甲醛的时期，之后生长才能恢复。对BIP菌株中甲醛诱导蛋白进行的二维电泳和质谱表征显示，甲醛代谢途径以及对甲基营养生长的适应性与在特征明确的利用甲醇的甲基营养菌——嗜甲基甲基杆菌AM1中观察到的非常相似。因此，似乎使BIP菌株能够利用高浓度甲醛生长的许多蛋白质表达变化与嗜甲基甲基杆菌AM1在利用甲醇生长过程中作为代谢中间产物处理甲醛时所使用的相同酶的表达有关。
