Methanol Dehydrogenases as a Key Biocatalysts for Synthetic Methylotrophy

Abstract

One-carbon (C1) chemicals are potential building blocks for cheap and sustainable re-sources such as methane, methanol, formaldehyde, formate, carbon monoxide, and more. These resources have the potential to be made into raw materials for various products used in our daily life or precursors for pharmaceuticals through biological and chemical processes. Among the soluble C1 substrates, methanol is regarded as a biorenewable platform feedstock because nearly all bioresources can be converted into methanol through syngas. Synthetic methylotrophy can be exploited to produce fuels and chemicals using methanol as a feedstock that integrates natural or artificial methanol assimilation pathways in platform microorganisms. In the methanol utilization in methylotrophy, methanol dehydrogenase (Mdh) is a primary enzyme that converts methanol to formaldehyde. The discovery of new Mdhs and engineering of present Mdhs have been attempted to develop synthetic methylotrophic bacteria. In this review, we describe Mdhs, including in terms of their enzyme properties and engineering for desired activity. In addition, we specifically focus on the application of various Mdhs for synthetic methylotrophy.

One-Pot Biosynthesis of 2-Keto-4-hydroxybutyrate from Cheap C1 Compounds Using Rationally Designed Pyruvate Aldolase and Methanol Dehydrogenase

“…8−10 Oxidation of methanol to formaldehyde by methanol dehydrogenase (MDH), one of the key steps in methanol utilization, is the initial and rate-limiting step in methanol bioconversion because of its low catalytic activity and substrate affinity. 11,12 MDH is also thermodynamically unstable. In the previous study, we successfully engineered the methanol dehydrogenase from Lysinibacillus xylanilyticus (LxMDH) to possess much higher catalytic efficiency than the wild-type enzyme.…”

“…Among C 1s, formaldehyde is an emerging C1 substrate since it can be diversely prepared from carbon monoxide (CO), carbon dioxide (CO 2 ), formic acid (HCOOH), methane (CH 4 ), and especially methanol (CH 3 OH) by biological or chemical means. , Especially, methanol is interesting because it is produced also from biomass-derived synthesis gas and reduction of CO 2 and is generally available at a cheaper price than sugar. − Oxidation of methanol to formaldehyde by methanol dehydrogenase (MDH), one of the key steps in methanol utilization, is the initial and rate-limiting step in methanol bioconversion because of its low catalytic activity and substrate affinity. , MDH is also thermodynamically unstable. In the previous study, we successfully engineered the methanol dehydrogenase from Lysinibacillus xylanilyticus ( Lx MDH) to possess much higher catalytic efficiency than the wild-type enzyme. , Conversion of formaldehyde into value-added molecules is substantially challenging because of its toxicity and symmetrical reactivity.…”

Adaptive evolutionary strategy coupled with an optimized biosynthesis process for the efficient production of pyrroloquinoline quinone from methanol

“…The explanations for the increase in PQQ biosynthesis by this methylotrophic bacterium at pH 7.0 might be that the pqqA promoter was induced, resulting in the upregulation of PQQ precursor [20]. The PqqC protein involved in the oxidation of AHQQ to PQQ may have exhibited higher activity [42], and methanol dehydrogenase functioned better near its optimal pH value [46] when the host was transferred from pH 6.5 to pH 7.0. Noticeably, the μ x value at pH 6.5 was lower than that at other pH values after 40 h. Therefore, a two-stage pH control strategy was designed to increase PQQ biosynthesis; namely, a pH value of 6.5 favored cell growth and metabolism in the initial fermentation, and a pH value of 7.0 would increase PQQ synthesis after 40 h of fermentation.…”

In Vitro One-Pot 3-Hydroxypropanal Production from Cheap C1 and C2 Compounds

“…Methanol (C1) and ethanol (C2) are major compounds considered next generation substrates that can be converted to natural metabolite products, such as acetaldehyde, formaldehyde, and acetyl-CoA-derived products, in microorganisms via short biosynthetic pathways. Various biocatalysts, such as alcohol oxidase, oxidoreductase, and methanol dehydrogenase (MDH), have been considered to convert methanol and ethanol [ 9 , 10 ]. Among these enzymes, MDH (EC 1.1.1.244) is a key enzyme for alcohol oxidation, which catalyzes alcohol conversion to aldehyde [ 11 ].…”