The first modularized circuit is the blue light inducible system modified from the arabinose operon. As shown in the figure, the Arabinose binding and dimerization domain of native AraC protein was replaced with blue light responsive VVD domain, generating VVD-AraC fusion regulatory protein. Then the modified arabinose operon will regulated by blue light (470nm) instead of arabinose. Three different promoters are selected for the expression of VVD-AraC fusion protein to find the optimal one.

The second modular circuit mainly contains AstABC gene cluster for the synthesis of aspartic acid, under IPTG-inducible Ptrc promoter. It will convert the FPP generated by the precursor plasmid to aspartic acid. The broad-host-vector pBBRMCS1 is used as the backbone. Specific terminators（transcription terminator T1 from the E. coli rrnB gene）and three ribosome binding sites between AA gene clusters were added.

The third modular circuit is for the synthesis of exopolysaccharides (EPS), including the EPS synthesis gene pmgA and galU under the control of Ptrc promoter. This is our improved version of the EPS synthetic plasmid in team XJTU-iGEM in 2020.

We designed a fourth modular circuit for the biosafety and project feasibility. We synthesized the lytic gene and make it under the Pλ promoter to achieve the temperature control of bacterial lysis and product release. When the temperature is 42oC or higher, the regulatory protein of CI will degrade to allow the expression of lysis gene, and our engineered bacteria would break, releasing the product herbicide and EPS.