Construction method and application of optically pure meso-2,3-butanediol high-yield engineering strain

Abstract

The invention discloses construction of a high-yield engineering strain for optically pure meso-2,3-butanediol. A construction method comprises the following steps of carrying out codon optimization on nucleotide sequences of an alpha-acetolactic acid synthetase gene, an alpha-acetolactic acid decarboxylase gene and a meso-2,3-butanediol dehydrogenase gene, afterwards, splicing to obtain a gene cluster containing the three genes, then introducing the gene cluster into an expression vector to obtain a polycistronic recombinant plasmid, and finally introducing the recombinant plasmid into a host bacterium E. coli again, so that a high-yield engineering bacterium is obtained. Synthesis raw materials used by the bacterium are wide in sources and low in costs; the strain has no pathogenicity; the strain is high in yield, high in production efficiency and good in stability, has the highest yield which can reach 91.5g / L and the optical purity which can reach 99 percent or above. The invention discloses application of the high-yield engineering strain to the production of the optically pure meso-2,3-butanediol by utilizing cheap cassava meal as a carbon source and utilizing cottonseed protein powder, soybean pulp powder, soybean cake powder or peanut protein powder as a nitrogen source at the same time. The production cost is lowered.

Description

technical field [0001] The invention belongs to the field of biotechnology, in particular to a method for constructing an optically pure meso-2,3-butanediol high-yielding engineering strain and its application in producing optically pure meso-2,3-butanediol using cheap raw materials . Background technique [0002] 2,3-butanediol (2,3-butanediol) is a platform compound, which has wide application value in chemical industry, food, energy, medicine and other fields. Its microbial fermentation production is an important topic of modern biochemical industry. The 2,3-butanediol molecule contains two chiral carbon atoms, so there are three optical isomers, namely (2R,3R)-2,3-butanediol, (2S,3S)-2, 3-butanediol and meso-2,3-butanediol. The single-configuration meso-2,3-butanediol not only possesses the basic functions of the meso-2,3-butanediol, but also has great potential advantages in the asymmetric synthesis of high value-added chemicals and drugs, such as using It has broad ...

AI Technical Summary

Problems solved by technology

The highest yield of meso-2,3-butanediol in this engineering strain is 85g / L, but the optical purity is too low, only 96%, and high-priced raw materials yeast powder and glucose are needed to achieve high yield

In addition, pET-28a(+) is a high-copy expression vector, and this method needs to induce and express a large number of genes (lysR, budA, budB, and budC), which increases the metabolic load of the host and increases the cost of large-scale industrial production. instability

However, the current method of fermenting and producing meso-2,3-butanediol using cheap carbon sources results in low production of meso-2,3-butanediol due to insufficient production capacity of the strain, or the optical purity does not meet the requirements

To sum up, there are problems such as high cost of raw materials, low optical purity, low yield, or unstable strains in the existing synthesis technology of meso-2,3-butanediol.

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