This method has great potential to expand the functionality of biomolecular devices and can be used to separate growth and production processes during fermentation. Based on the specificity of hyaluronic acid produced by multiple metabolic pathways, we applied the designed bistable switch to regulate the carbon flow direction of engineering bacteria fermenting hyaluronic acid and tested the degree of performance improvement after optimizing the switch. We attempted to construct a bistable switch using ordinary Escherichia coli. Due to the production of hyaluronic acid by the precursors UDP-glucuronic acid and UDP N-acetyl-glucosamine in the glucose metabolism pathway of E. coli under the action of hasA, we plan to use arabinose operons to regulate the galU and udg gene pathways in the UDP-glucuronic acid biosynthesis pathway of E. coli; In the biosynthesis pathway of UDP-N-acetyl-glucosamine, tetracycline operons are used to regulate gene pathways such as glmU, glmS, and glmM[5]. We plan to regulate the ratio of opening of the two pathways by changing the concentration of added inducers arabinose and dehydrated tetracycline, and during the growth process, make the metabolic pathway more inclined towards growth-related pathways, allowing the strain to grow rapidly first. During the fermentation process, the metabolic pathway is biased towards the pathway that produces fermentation products, allowing the strain to produce a large amount of fermentation products. In the testing phase, we used GFP instead of the relevant genes in order to more accurately and quickly detect the performance of the mutants. After the design of the bistable switch was completed, we used error-prone PCR and computer simulation to evolve araC and tetR genes directly, to optimize the bistable switch, increase its ability to inhibit protein binding to DNA, reduce promoter leakage, and increase the performance of the bistable switch.