The construction of plasmids carrying the gene argAfbr greatly improved the conversion of ammonia. Compared with wildtype DH10b, the expression of argAfbr and argR knockout led to 40.47% more consumption on ammonia, which, statistically, was consistent with our expectation.
As for the hydrogen sulfide pathway, the best mutation of cysE gene caused a significant increase on conversion of H2S into cysteine which converted and produced 98.72% more cysteine compared with wildtype.
According to the verification, we have successfully constructed the plasmids to produce myrcene. The concentration of myrcene produced by E.coli was 0.034735 mg/ml. This showed that DH10b with plasmids pMevT, pMBIS, and pBR322-KanR-Ptac-GPPS-MS could produce myrcene.
In the modeling part, we simulated the growth curves of the three stains in a single environment. From the result of the model, we figured out that when the ratio of three strains is 8:4:7, our product could function for about 80 hours, which theoretically proved that our product was plausible.
Our final product was a capsule that composed of all the three types of strains; consequently, we designed an experiment in which these strains were mixed together in different ratio and tested in the same way used in the experiment of testing consumption of NH3 and H2S. Although the result seemed unsatisfactory, we still discovered a trend that all these three strains were able to keep alive and function regularly.
According to the interview with the vice CEO of the biomedical company XBiome, the vice CEO believed that our product would have positive effect and great meanings.