Engineering strain capable of producing high-content zeaxanthine or astaxanthin and application thereof

Abstract

The invention discloses an engineering strain capable of producing high-content zeaxanthine or astaxanthin and application thereof. The engineering strain capable of producing the high-content zeaxanthine or astaxanthin carries a crtE gene, a crtB gene, a crtI gene, a crtY gene and a crtZ gene, wherein the copy number ratio of the crtY gene to the crtZ gene is preferably 1 to 2; the engineering strain capable of producing the high-content zeaxanthine or astaxanthin also carries at least one crtW gene, the copy number ratio of the crtW gene, the crtZ gene and the crtY gene is preferably 1 to 2 to 1; the used crtY gene and crtZ gene are preferably selected from pantoea ananatis, the crtW gene is preferably selected from brevundimonas, and plasmid-free engineering escherichia coli is preferably selected as the engineering strain. The content of the zeaxanthine or astaxanthin produced by the built engineering strain accounts for more than 90 percent of total carotenoids, the problems that the content of target products is low, the purification is difficult are solved, and the engineering strain can be applied to preparation of high-purity zeaxanthine or astaxanthin.

Description

technical field [0001] The invention relates to the field of genetic engineering, in particular to engineering bacteria producing high-content zeaxanthin or astaxanthin and applications thereof. Background technique [0002] Zeaxanthin and astaxanthin are important carotenoids. Among them, zeaxanthin is clinically used to treat age-related macular degeneration. Astaxanthin, as the antioxidant with the strongest antioxidant capacity found, has anti-oxidation, skin and eye protection, radiation resistance, cardiovascular aging, senile dementia and cancer effects in clinical practice. [0003] The heterologous synthesis of zeaxanthin and astaxanthin by microorganisms has become a research hotspot, generally by introducing exogenous carotenoid synthesis pathway genes into the chassis bacteria. The synthesis of zeaxanthin and astaxanthin starts from FPP and passes through crtE, crtB, crtI , crtY continuous catalysis to generate β-carotene, β-carotene is catalyzed by crtZ to pro...

AI Technical Summary

Problems solved by technology

However, due to the nonspecificity and substrate nonspecificity of these two enzymes, crtZ and crtW, a series of intermediate metabolites are often generated during the reaction, such as lycopene, β-carotene, canthaxanthin, marigold Anthocyanin, cryptoxanthin and echinenone, etc., lead to the content of the target products zeaxanthin and astaxanthin in the total carotenoids below 80%. These intermediate products belong to the same carotenoids as the target products, and their molecular structures Very similar, it is difficult to separate and purify by ordinary chemical methods, even if high-yielding zeaxanthin and astaxanthin strains are obtained, the low content of the target product limits the preparation of high-purity single zeaxanthin or astaxanthin

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