S-Adenosyl-l-methionine production by Saccharomyces cerevisiae SAM 0801 using dl-methionine mixture: From laboratory to pilot scale

Abstract

This study sought to develop a cost-effective biological catalysis process for S-adenosyl-L-methionine (SAM) production. During the process, a mixture of D-methionine (D-Met) and L-methionine (L-Met), namely DL-Met, was used as substrate to replace the conventional but expensive pure L-Met. The concentration of DL-Met in substrate was optimized. When 80 g/L of DL-Met was added in a 5 L-scale bioreactor, 13.74 g/L of SAM was produced with an L-Met conversion rate of 32.15%. The fermentation process was then scaled up to meet the requirements of realistic industrial SAM production. In a 300 L-scale fermentation process, 10.45 g/L of SAM was achieved, with an L-Met conversion rate of 32.61%. Moreover, the proportion of D-Met remaining in broth increased from 50% at the beginning to 76.89% at the end of fermentation. The fermentation process is generally appropriate for commercial SAM production.

Metabolic engineering of Bacillus amyloliquefaciens for enhanced production of S-adenosylmethionine by coupling of an engineered S-adenosylmethionine pathway and the tricarboxylic acid cycle

“…Consequently, methionine is usually added directly into the medium as a fermentation substrate to produce SAM and various previous studies have aimed to improve SAM production from methionine, including fermentation optimization, conventional mutation breeding, and genetic engineering [7, 14]. The conversion rate from expensive methionine to SAM ranges from 15 to 42% [15–17], resulting in high cost. Therefore, development of efficient SAM production methods using methionine-free medium is much needed.…”

Efficient production of S‐adenosyl‐l‐methionine from dl‐methionine in metabolic engineered Saccharomyces cerevisiae

“…Although l ‐methionine was often fed for SAM biosynthesis in yeast (Kanai, Mizunuma, Fujii, & Iefuji, ; Ren et al, ), dl ‐methionine should be a more suitable substrate for industrial SAM production, due to the much lower cost. As l ‐methionine is the specific substrate of SAM synthetase, d ‐methionine was wasted and even resulted in toxicity to yeast cells (Rytka, ; Yow et al, ; Figure ).…”

“…Compared with the strains using l ‐methionine as the substrate, the recombinant strain HDL‐R2 showed comparable SAM production by feeding cheaper dl ‐methionine. Ren et al () reported that 10.2 g/L SAM with a content of 78.2 mg/g DCW was accumulated in an industrial S. cerevisiae SAM0801 by feeding 40 g/L dl ‐methionine, while 10.9 g/L SAM with a content of 78.9 mg/g DCW was obtained by feeding 20 g/L l ‐methionine, suggesting that d ‐methionine was not converted to l ‐methionine in vivo. To the best of our knowledge, it was the first time to engineer S. cerevisiae for efficient SAM production from low‐cost dl ‐methionine via the conversion of d ‐methionine to l ‐methionine.…”

“…However, l ‐methionine was fed as the substrate for SAM production in most cases (Huang et al, ; Kamarthapu, Ragampeta, Rao, & Reddy, ; Zhang, Wang, Su, et al, ; Zhao, Hang, et al, ; Zhao, Shi, et al, ). Only one‐third of the price of l ‐methionine (Ren et al, ; Zhang, Gedicke, Kuznetsov, Staroverov, & Seidel‐Morgenstern, ), dl ‐methionine could be the cost‐saving substrate for industrial production of SAM. However, d ‐methionine transported into the cell through the general amino acid permease (Gap1p) cannot be incorporated for SAM biosynthesis and inhibit the cell growth to a certain extent.…”

Engineering Pichia pastoris to improve S‐adenosyl‐l‐methionine production using systems metabolic strategies

“…Another strategy adopted was increment of intracellular l ‐Met levels and redirection of methionine to SAM biosynthesis, such as optimization of the l ‐Met feeding in an engineered P . pastoris strain (Hu et al, 2009b) and using dl ‐Met (a mixture of d ‐Met and l ‐Met) as a substrate for SAM production in a mutant Saccharomyces cerevisiae (Ren et al, 2017). In fact, it is essential to optimize culture conditions for a newly constructed strain, since physiological characteristics are strain/clone specific and not predictable a priori.…”