Identification of two mutations increasing the methanol tolerance of Corynebacterium glutamicum.
Identification of two mutations increasing the methanol tolerance of Corynebacterium glutamicum.
复制标题
DOI：
10.1186/s12866-015-0558-6
复制
发表时间：
2015-10-16
期刊：
影响因子：
4.2
通讯作者：
Wendisch VF
中科院分区：
文献类型：
--
作者：
Leßmeier L;Wendisch VF
甲醇存在于大多数生态系统中，也可能出现在工业应用中，例如作为碳源（如工业甘油）的杂质。甲醇通常抑制细菌的生长，因此，甲醇耐受性可能会限制发酵生产过程。在甲醇存在下，通过实验进化提高了土壤氨基酸产生菌谷氨酸棒杆菌的甲醇耐受性。所得菌株Tol 1在高达1 M甲醇的存在下表现出显著增加的生长速率。然而，既没有观察到线性甲醇氧化途径的转录变化，也没有观察到线性甲醇氧化途径的酶活性增加，这与对下游代谢物甲醛和甲酸盐的耐受性没有改善的发现一致。Tol 1菌株的基因组序列分析揭示了两个可能与增强的甲醇耐受性相关的点突变：一个导致O-乙酰高丝氨酸硫水解酶MetY的氨基酸交换A165 T，另一个导致缩短的CoA转移酶Cat（Q342*）。将任一突变导入C. glutamicum野生型增加了甲醇耐受性，将两种突变引入C.谷氨酸足以获得甲醇耐受性，几乎与菌株Tol 1的甲醇耐受性没有区别。甲醇耐受性较好。谷氨酸可以通过两个点突变来增加，导致O-乙酰高丝氨酸硫酸水解酶MetY和缩短的CoA转移酶Cat的氨基酸交换。当使用含有甲醇作为组分或杂质的碳源时，将这些突变引入生产菌株可能会有所帮助。本文的在线版本（doi：10.1186/s12866-015-0558-6）包含补充材料，可供授权用户使用。
Methanol is present in most ecosystems and may also occur in industrial applications, e.g. as an impurity of carbon sources such as technical glycerol. Methanol often inhibits growth of bacteria, thus, methanol tolerance may limit fermentative production processes. The methanol tolerance of the amino acid producing soil bacterium Corynebacterium glutamicum was improved by experimental evolution in the presence of methanol. The resulting strain Tol1 exhibited significantly increased growth rates in the presence of up to 1 M methanol. However, neither transcriptional changes nor increased enzyme activities of the linear methanol oxidation pathway were observed, which was in accordance with the finding that tolerance to the downstream metabolites formaldehyde and formate was not improved. Genome sequence analysis of strain Tol1 revealed two point mutations potentially relevant to enhanced methanol tolerance: one leading to the amino acid exchange A165T of O-acetylhomoserine sulfhydrolase MetY and the other leading to shortened CoA transferase Cat (Q342*). Introduction of either mutation into the genome of C. glutamicum wild type increased methanol tolerance and introduction of both mutations into C. glutamicum was sufficient to achieve methanol tolerance almost indistinguishable from that of strain Tol1. The methanol tolerance of C. glutamicum can be increased by two point mutations leading to amino acid exchange of O-acetylhomoserine sulfhydrolase MetY and shortened CoA transferase Cat. Introduction of these mutations into producer strains may be helpful when using carbon sources containing methanol as component or impurity. The online version of this article (doi:10.1186/s12866-015-0558-6) contains supplementary material, which is available to authorized users.