Method for synthesizing ergothioneine by utilizing escherichia coli cell factory fermentation

The invention provides a method for fermenting and synthesizing ergothioneine by using an escherichia coli cell factory, and aims to construct a novel escherichia coli cell factory taking methionine, histidine and cysteine as substrates so as to realize fermentation synthesis of ergothioneine. The method comprises the following steps: firstly, by taking E.coli BL21 (DE3) as a host, co-expressing histidine betaine oxygenase (EgtB), histidine N-alpha-methyltransferase (EgtD), cysteine sulfoxide lyase (EgtE) and S-adenosylmethionine synthetase (MetK) by utilizing a pRSFDuet-1 and pACYCDuet-1 dual-plasmid system, and constructing an intracellular synthesis path of ergothioneine; secondly, optimizing the amount, temperature and substrate concentration fermentation process of IPTG (isopropyl-beta-d-thiogalactoside) in sequence to further enhance the production efficiency of the cell factory; finally, the expression level of the key gene is improved by using the SUMO fusion tag, and the final ergothioneine yield can