Method for improving organic selenium synthesis ability of microorganisms based on sulfur-containing protein overexpression, and application thereof

Abstract

The invention discloses a method for improving the organic selenium synthesis ability of microorganisms based on sulfur-containing protein overexpression , and belongs to the technical field of biosynthesis of organic selenium. An exogenous sulfur-containing protein gene is introduced into a microbial genome, and the obtained genome is cultured in a high-selenium and low-sulfur environment. Sulfurin sulfur-containing amino acids (cysteine and methionine) is replaced by selenium during the overexpression of an exogenous sulfur-containing protein to synthesize selenosulfate amino acid in order to synthesize a selenoprotein, so efficient organic selenium synthesis of the microorganisms is achieved. The method is based on a substitution competition relationship between selenium and sulfur,a process for synthesizing the organic selenium by using the selenoprotein is provided, the sulfur-containing foreign protein is constructed in a biotechnical way, and the selenoprotein that is the organic selenium is formed in transferred microorganisms. The method can efficiently enrich selenium and ensure the safety.

Description

technical field [0001] The invention belongs to the technical field of selenium enrichment, in particular to the technical field of organic selenium production, and relates to a method and application for improving microbial organic selenium synthesis ability / effect based on the overexpression of sulfur-containing proteins. Background technique [0002] Selenium is an indispensable nutrient element for the human body. In the human body, selenium can resist viruses, delay aging, regulate the human immune system, and also have various functions such as improving vision, improving memory, preventing rheumatic bone pain, breathing, and gastrointestinal diseases. Selenium deficiency can lead to cancer, diabetes, cardiovascular disease, and immune system disease. [0003] Compared with other essential trace elements for the human body, the distribution of selenium in the earth's crust is extremely uneven around the world, and high-selenium soils are often located in relatively sma...

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Problems solved by technology

[0006] At present, the main method to improve the selenium-enrichment ability of microorganisms is to obtain starting strains with higher selenium tolerance through artificial screening, and to increase the inorganic selenium content in the medium during the fermentation process so that microorganisms can enrich more selenoproteins to improve microbial growth. The organic selenium content in the body, but so far only found that brewer's yeast has a high ability to tolerate selenium, which may be related to its original high protein content

However, the nutritional conditions of brewer's yeast are harsh, and the yield when used in the production of selenium-enriched yeast is low, resulting in high production costs. The price of selenium-enriched yeast products is very high, exceeding the consumption capacity of ordinary people

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