Team:BGU-Israel/safety
Safe Project Design
Our project's goal is to decompose cellulose fibered wet wipes in the sewer systems to prevent the formation of "fatbergs" and clogs.
Since cellulose cannot cross the cellular membrane, we engineered E. coli to express cellulolytic complex on its surface through an AIDA-1 auto-display system.
Our cellulolytic complex included cellulase linked to CBD (cellulose binding domain).
We used DH5-Alpha commercial competent cells in our transformation protocol. This strain is considered Risk Group 1 organism that does not cause disease in healthy adult humans. Moreover, we avoided conducting some experiments on grounds of lab safety. For example, we wanted to work with Phage Lambda in our project as a mean of transduction. In the end, to prevent risk to other lab members who work with E. coli, we decided not to conduct these experiments.
We have consulted several environmental experts and sewage corporations' directors regarding the safety of the project and the future idea of releasing engineered E. coli to sewerage systems. Their response was it would not pose an additional risk due to the following reasons:
- Raw sewage (RS) and wastewater already contain pathogens such as bacteria, viruses, protozoa and parasites. E. coli strains exist in RS and wastewater, therefore, release of engineered E. coli to sewerage system is not hazardous.
- In the Wastewater treatment process, the last step is disinfection by chemical oxidation (in Israel by adding chlorine) that kills bacteria and microbial pathogens. Our engineered E. coli would also be killed in this disinfection.
In our lab experiments we involve antibiotic resistant gene in the plasmids to verify the insertion into the recombinant bacteria. In the future, the engineered E. coli that will be released to the sewerage system, would not obtain antibiotic resistance. Therefore, a different plasmid will be designed without the resistant gene.
Safe Laboratory Work and Conduct
During our project, we followed Ben-Gurion University laboratory biosafety regulations and guidelines. As part of this, all team members received safety training prior to conducting any laboratory work. Experiment protocols were preformed only after one of the staff lab members confirmed we are capable of. At no point, one of us was working alone in the lab space, there was always a second person in the space for safety.
All team members used personal protective equipment (PPE) while working in the lab. This includes protective clothing, face mask, closed toe shoes and laboratory coats.
In order to keep the work environment clean and disinfected, before and after lab work was conducted on the open bench, surfaces were sterilised with 70% ethanol.
On top of that, when sterile work was conducted on the open bench, a burner was used to keep the area sterile and prevent contamination.
Due to a second covid-19 related lockdown imposed on Israeli residents for several weeks in September 2020, the iGEM-lab has been closed and our team had to abandon the lab work. At this point, we relied mostly on working remotely and lab safety issues became irrelevant.
Team members Omer and Judith work safely in the chemical hood!
Team members Omer, Talia and Judith work safely on our open bench!
Team members Omer and Judith work safely in the chemical hood!