Design And Construction Of Artificial Microbial Mixture Systems For Degradation Of PET Plastic And Synthesis Of Rosmarinic Acid

The increased complexity of the artificial anabolic network brings an increase in the physiological burden of the chassis microorganisms.It has become an important research direction of synthetic biology to simulate the natural flora for complex target biological processes.In this study,the principle of the design and construction of the synthetic microbial mixture system for substance synthesis and degradation function was explored by taking the allogenic biosythesis of the high value-added product Rorosemary acid(RA)and the green biodegradation of polyethylene terephthalate(PET)as examples.For the biodegradation of PET plastics,PET monomer BHET was taken as the research object,and a microbial co-culture degradation system composed of two metabolically engineered Bacillus subtilis was designed and constructed.Finally,100 mg BHET was achieved within 22 hours.Completely degraded.To overcome the toxicity of the degradation product TPA,PET was further degraded by the introduction of Rhodococcus jostii RHA1.The degradation time of 100 mg BHET was reduced to 20 h.When this microbial consotrium was applied to the biodegradation of PET,the quality of the membrane was reduced by 10.6 mg within 6 days,and the degradation effect reached 31.2%,which was 2.72 times higher than that of the single bacterial degradation system.Rosmarinic acid contains two structural units,caffeic acid and Salvianic acid A.In this study,an engineered saccharomycete containing tyrosine deaminase(TAL)and hydroxylase(Hpa B and Hpa C)transformation pathway was constructed to produce caffeic acid using tyrosine as substrate.A three-bacteria system was designed and constructed,consisting of the engineered Saccharomyces cerevisiae producing caffeic acid,the engineered Escherichia coli producing Salvianic acid A and the E.coli expressing the rosmarinic acid synthase.The de novo allogenic biosythesis of rosmarinic acid was realized,and the yield of rosmarinic acid reached 38.78 mg/L after 120 h fermentation.This study provides a new idea for the future rational design of more complex compounds by efficient synthetic microbial consortia,which can be applied in the fields of bioenergy and environmental remediation.