Improvement of d‐lactic acid productivity by introducing Escherichia coli acetyl‐CoA synthesis pathway in engineered Saccharomyces cerevisiae

Abstract

BACKGROUND d‐Lactic acid (d‐LA) is gaining increased attention as it can be applied in the food, pharmaceutical, cosmetic, polylactic acid and textile industries. Acid‐tolerant Saccharomyces cerevisiae is often engineered to produce organic acids. For the pyruvate decarboxylases (PDCs) or alcohol dehydrogenase 1 (ADH1) disrupted strains, the productivity of d‐LA significantly decreases due to the accumulation of acetaldehyde and acetic acid. To overcome the problem, Escherichia coli acetylating acetaldehyde dehydrogenase (A‐ALD) enzyme genes (MHPF and EUTE) (EC 1.2.1.10) were integrated into the d‐LA producing strain YIP‐A15G12 strain (CGMCC2.5803). The function of these genes is to directly convert acetaldehyde into acetyl‐CoA without energy consumption. This strain was integrated with Escherichia coli d‐lactate dehydrogenase and Issatchenkia orientalis glycosylphosphatidylinositol‐anchored protein IoGas1gene and several attenuated key pathway genes, including PDC1, PDC6, ADH1, ADH5, JEN1 (a monocarboxylate transporter), d‐lactate dehydrogenase 1 (DLD1), l‐lactate cytochrome c oxidoreductase (CYB2) and glycerol‐3‐phosphate dehydrogenases (GPD1, GPD2). RESULTS The strain expressions of the A‐ALD enzymes effectively complemented the attenuated acetaldehyde dehydrogenase (ALD) acetyl‐CoA synthetase (ACS) pathway and significantly improved the levels of acetyl‐CoA and the productivity of d‐LA. Finally, the resulting strainYIP‐m‐ald6 (CGMCC2.5826) produced 86.9 g L–1 d‐LA with a yield of 0.77 g g–1 glucose and a volumetric productivity of 1.77 g L–1 h–1 at pH 3.58 under fed‐batch fermentation conditions. CONCLUSION Introducing the E. coli acetyl‐CoA synthesis pathway into the yeast strain can significantly enhance the growth of the strain and improve the d‐LA productivity, as a benefit for d‐LA production in industry. © 2021 Society of Chemical Industry (SCI).

Metabolic Engineering of Saccharomyces cerevisiae for Vitamin B5 Production

“…47 Knocking out pyruvate decarboxylase Pdc1 and acetaldehyde dehydrogenase Ald6 was also an effective strategy to increase the pyruvate pool by weakening the synthesis of acetate. 48 However, the titer of D-pantothenic acid in strain DPA142, DPA143, or DPA151 did not increase substantially. It was similar to the situation of knocking out Lpd1 (DPA146) leading to a branch to tricarboxylic acid cycle.…”

“…This may be attributed to the fact that the elimination of the glycerol pathway improves not only the pyruvate flux but also the serine flux and increases the catalytic efficiency of KPHMT . Knocking out pyruvate decarboxylase Pdc1 and acetaldehyde dehydrogenase Ald6 was also an effective strategy to increase the pyruvate pool by weakening the synthesis of acetate . However, the titer of d -pantothenic acid in strain DPA142, DPA143, or DPA151 did not increase substantially.…”

β-Glucan Enhances the Biocontrol Efficacy of Marine Yeast Scheffersomyeces spartinae W9 against Botrytis cinerea in Strawberries

“…The gene ADH1 encodes alcohol dehydrogenase, which is the primary enzyme for the reoxidation of NADH in yeast. Zhong et al (2021) showed that inactivation of ADH1 caused the accumulation of NADH, resulting in the imbalance of NADH/NAD and growth retardation [52]. The upregulation of ACH1 and ADH1 in S. spartinae W9 cells cultured with 0.1% β-glucan led to higher colonization ability in strawberry wounds and improved biocontrol efficacy.…”

Green acetyl modification of puerarin to form puerarin 6′′-O-acetate using engineered Escherichia coli with favorable pathways and elevated acetyl-CoA supply

“…20 The genes encoding PDH complex, ACS, PANK and other acetyl-CoA forming enzymes were introduced into microorganisms to generate diverse cell factories overproducing acetyl-CoA. 18,21–23 These cell factories were generally used as a chassis for producing acetyl-CoA-derived chemicals. 21–24 The biosynthesis of P6′′A using self-producing acetyl-CoA, however, in cell factories has never been documented.…”

“…18,21–23 These cell factories were generally used as a chassis for producing acetyl-CoA-derived chemicals. 21–24 The biosynthesis of P6′′A using self-producing acetyl-CoA, however, in cell factories has never been documented.…”