Center for Bioengineering and Biotechnology, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China.
Center for Bioengineering and Biotechnology, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, China; College of Chemistry and Materials, Fujian Normal University, Fuzhou, 350007, China.
J Biotechnol. 2017 Oct 10;259:26-29. doi: 10.1016/j.jbiotec.2017.08.008. Epub 2017 Aug 18.
Acyloins are useful organic compounds with reactive adjacent hydroxyl group and carbonyl group. Current research is usually constrained to acetoin (i.e. 3-hydroxy-2-butanone) and the biological production of other acyloins was scarcely reported. In this study, two hydroxy-pentanone metabolites (3-hydroxy-2-pentanone and 2-hydroxy-3-pentanone) of Bacillus sp. H15-1 were identified by gas chromatography-mass spectrometry and authentic standards. Then the complete genome of this strain was sequenced and de novo assembled to a single circular chromosome of 4,162,101bp with a guanine-cytosine content of 46.3%, but no special genes were found for the biosynthesis of the hydroxy-pentanones. Since hydroxy-pentanones are the homologues of acetoin, the two genes alsD and alsS (encoding α-acetolactate decarboxylase and α-acetolactate synthase, respectively) responsible for acetoin formation in this strain were respectively expressed in Escherichia coli. The purified enzymes were found to be capable of transforming pyruvate and 2-oxobutanoate to the two hydroxy-pentanones. This study extends the knowledge on the biosynthesis of acyloins and provides helpful information for further utilizing Bacillus sp. H15-1 as a source of valuable acyloins.
乙酰醇是一类具有反应性相邻羟基和羰基的有用有机化合物。目前的研究通常局限于乙酰丙酮（即 3-羟基-2-丁酮），而其他乙酰醇的生物合成则鲜有报道。在这项研究中，通过气相色谱-质谱联用仪和标准品鉴定了芽孢杆菌 H15-1 的两种羟基戊酮代谢物（3-羟基-2-戊酮和 2-羟基-3-戊酮）。然后，对该菌株的完整基因组进行了测序和从头组装，得到了一条 4,162,101bp 的单环状染色体，鸟嘌呤-胞嘧啶含量为 46.3%，但没有发现专门用于合成羟基戊酮的基因。由于羟基戊酮是乙酰丙酮的同系物，因此负责该菌株乙酰丙酮形成的两个基因 alsD 和 alsS（分别编码α-乙酰乳酸脱羧酶和α-乙酰乳酸合酶）分别在大肠杆菌中进行了表达。发现纯化后的酶能够将丙酮酸和 2-氧代丁酸转化为两种羟基戊酮。本研究扩展了对乙酰醇生物合成的认识，并为进一步利用芽孢杆菌 H15-1 作为有价值的乙酰醇来源提供了有价值的信息。
