Production of Methionol from 3-Methylthiopropionaldehyde by Catalysis of the Yeast Alcohol Dehydrogenase Adh4p

Abstract

Methionol is a sulfur-containing aroma compound that contributes to the flavors of fermented foods. In this work, a novel method for methionol production was established using 3-methylthiopropionaldehyde (MMP) and alcohol dehydrogenase (ADH). First, expression of seven ADH genes was analyzed in yeast fermentation added with MMP. Only ADH4 displayed an evident increased expression in response to MMP. ADH4 was then overexpressed in Saccharomyces cerevisiae S288c and Escherichia coli BL21. The recombinant yeast strain S4 produced more methionol than control strain in MMP fermentation. Furthermore, 0.55 g/L 42 kDa Adh4p was prepared from E. coli by induced expression and purification. A fed-batch catalysis system was finally established to produce methionol from MMP by Adh4p. In 10 h of continuous catalysis, the conversion rate of MMP remained 80− 95%, and a final yield of 0.2 g/L methionol was achieved. This work proposed a novel method for methionol production by enzymatic catalysis with a potential application prospect in industry.

Screening of Yeasts Isolated from Baijiu Environments for Producing 3-Methylthio-1-propanol and Optimizing Production Conditions

“…3-Methylthio-1-propanol (3-Met), a sulfur-containing higher alcohol, is a crucial aroma component of many foods and beverages, such as soy sauce, cheese, Baijiu , beer and wine and is naturally present in apples, tomatoes and other foods [ 1 ]. 3-Met has a low odor threshold of 1–3 ppm, with a recommended dosage in food of 0.1–10 mg/kg [ 2 ].…”

“…Chemical synthesis is mainly used because of its lower costs but it produces undesired side products, resulting in the formation of racemic mixtures and environmental pollution [ 3 , 4 ]. With the increasing demand of consumers for natural products, developing healthier and more eco-friendly natural products have become more important [ 1 , 3 , 4 ]. Microbial fermentation is a necessary process that uses microorganisms to transform raw materials into products needed by human beings through specific metabolic pathways under appropriate conditions [ 5 ].…”

“…Recent studies have shown that microorganisms, especially yeasts, can biotransform L-methionine (L-Met) to produce 3-Met by fermentation, an effective method of natural production [ 3 , 5 ]. L-Met is transaminated and then decarboxylated to the corresponding aldehydes via the Ehrlich pathway, then reduced to higher alcohols or oxidized to fusel acids [ 1 ]. In recent years, biological conversion methods have become an important development direction for producing natural 3-Met, because these methods could avoid undesired by-products and are considered as more eco-friendly [ 3 , 5 ].…”

Correlation between microbial community and flavour formation in dry-cured squid analysed by next-generation sequencing and molecular sensory analysis

“…Methanethiol is an important intermediate from Met metabolism, which is usually rapidly converted into dimethyl trisulphide through the Ehrlich pathway ( Lu et al, 2018 ). The production of methional is an enzymatic reaction mediated by Met aminotransferase and α-keto acid decarboxylase activity with Met as a precursor ( Che et al, 2020 ). In addition, the Maillard reaction between Met and ribose can also cause an increase in the amounts of methional and dimethyl trisulphide ( Liu et al, 2020 ).…”

Expanding the Application Range of Microbial Oxidoreductases by an Alcohol Dehydrogenase from Comamonas testosteroni with a Broad Substrate Spectrum and pH Profile

“…Therefore, they are a valuable class of enzymes to synthesize complex chiral products under mild reaction conditions and with high chemo-, regio-and stereoselectivity [5,6]. The resulting enantiomerically pure chemicals are essential chiral building blocks for the production of chiral pharmaceuticals, drugs or flavours [7,8]. NAD(P)(H)-dependent alcohol dehydrogenases (ADHs) represent one of the largest groups of biotechnologically applied oxidoreductases.…”