Application scenario and purposed users

We envision a GMOs release in the wastewater and our intended end users are water company and environmental company. The anthropogenic activities release PAHs into diverse environments like aquatic environments, deposition into surface water, soils, sediments, and air. Eventually, PAHs are enriched in the human body through the food chain and become a major problem for human health. Through a controlled release of our strains in urban sewerage system, we can reduce the harm of PAHs to the human body and the environment.

Preparation for release

Our strains have to work beyond the laboratory in a safe, stable, and traceable way. Therefore, we need to develop our existing genetic circuit. See the details below.

Biosafety concern

The biosecurity of GMOs used in the environment is a major concern. Before releasing GMOs in the real world, we must ensure that the escape frequency of our engineered E. coli strain is lower than 10-9, which meets the recommendation of US NIH guideline for GMOs release (<10-8). To achieve that, a self-controlled genetic circuit should be designed and carefully fine-tuned for programmable expression in E. coli. Cell behaviors are expected to be controlled by automatically sensing changes in PAHs concentration without any inducer requirement or manual interventions.

Ecological safety concern

Moreover, we must ensure that the release process has little impact on the indigenous ecosystem. An initial low concentration of biomass loaded (107 CFU ml−1 cells) will be inoculated into the model wastewater system, where the non-sterilized wastewater from the water company is used with an initial addition of 2 mM phenanthrene. Afterwards, we will analyze microbial diversity to evaluate the effect of the engineered cells on the indigenous microbial communities.