Overview

Safety is a foundational principle guiding all aspects of our project. From the initial planning to the execution of experimental procedures, we have prioritized the protection of both human health and the environment. Our experiments are conducted in a Biosafety Level 1 (BSL-1) laboratory, which is designed to handle agents that are not known to consistently cause disease in healthy individuals. This ensures a controlled and secure environment for all biological operations.

All biological materials used in our project, including Escherichia coli strains such as DH5α and BL21 (DE3), have been carefully selected and evaluated for their low-risk profile. These strains are non-pathogenic and non-invasive, and they do not possess the ability to survive or propagate in natural ecosystems. Furthermore, we have established a comprehensive waste management system to minimize any potential environmental impact. All biological and chemical waste is autoclaved at high temperatures prior to disposal, ensuring complete sterilization and eliminating any risk of contamination.

In addition to environmental safety, we have implemented strict operational guidelines to prevent any unintended consequences, such as horizontal gene transfer. The E. coli strains used in our project are not only non-pathogenic but also lacking the natural competence or conjugation mechanisms necessary for gene transfer. To further reduce the risk, all cultures and genetically modified organisms (GMOs) are handled in a closed system and are never released outside the laboratory unless properly inactivated.

Personnel Training

Every team member has undergone rigorous and systematic safety training before commencing any experimental work. The training program includes biosafety protocols, bioethics, and standard laboratory practices, all of which were delivered through the School of Life Sciences at Tianjin University. This curriculum is designed to equip students with both theoretical knowledge and practical skills in laboratory safety.

To ensure the effectiveness of the training, all team members are required to pass a mandatory lab safety entrance examination and a large-scale instrument operation training and assessment, and we have achieved a 100% pass rate with scores above 90. This demonstrates our team’s strong grasp of safety procedures and our commitment to maintaining a secure experimental environment. In addition, we conduct regular safety drills and knowledge reviews, reinforcing safe habits and ensuring that all members are consistently updated on best practices.

Protein Safety

The proteins studied in this project are various PET-degrading enzymes, which are biodegradation enzymes capable of catalyzing the decomposition of polyethylene terephthalate (PET). These enzymes are non-toxic, non-immunogenic, and have been widely studied under various controllable conditions for the degradation of PET. Their main function is to hydrolyze PET into monomer components, which can be recycled or safely degraded without posing a threat to human health or the ecosystem.

Strain Safety

The Escherichia coli strains employed in our project — DH5α and BL21 (DE3) — are standard laboratory strains widely used in molecular biology for cloning and protein expression. These strains are genetically stable, non-pathogenic, and have been approved for use in BSL-1 laboratories. They do not possess the virulence factors or horizontal gene transfer capabilities that could lead to environmental contamination.

Moreover, we have implemented stricter internal biosafety measures than the standard BSL-1 requirements. For instance, all cultures are handled in laminar flow hoods, and no live cultures are transported outside the lab unless fully inactivated. These precautions ensure that our work remains confined to a safe and controlled setting.

Gene Transfer Prevention

To address concerns regarding unintended gene transfer, we have taken multiple preventive measures throughout the project. First, we use non-pathogenic and non-motile E. coli strains, which lack the natural ability to transfer genes to other organisms. Second, all recombinant DNA work is performed in closed and sterile environments, minimizing the possibility of cross-contamination.

After experimental procedures, all biological materials are properly inactivated through autoclaving or chemical sterilization, depending on the nature of the waste. Additionally, we avoid the use of mobile genetic elements such as plasmids that can be transferred via conjugation, transformation, or transduction. Our project design is focused on containment and controlled expression, ensuring that no genetic material is released into the environment in any form.

Laboratory Safety

A dedicated laboratory safety officer has been assigned to our project to monitor and enforce all safety protocols. The laboratory is certified as BSL-1 and is equipped with essential safety infrastructure, including:

Personal Protective Equipment (PPE)

All team members are required to wear lab coats, gloves, safety goggles, and masks during experimental procedures. These measures are enforced to protect against chemical exposure, biological hazards, and physical injuries.

Chemical Management

We maintain a strict chemical inventory system, with all reagents labeled clearly and stored in designated, ventilated cabinets. Team members are trained to read Material Safety Data Sheets (MSDS) and follow proper handling and disposal procedures to prevent accidents and environmental hazards.

Facilities and Equipment Maintenance

All laboratory equipment is regularly inspected and maintained to ensure safe and efficient operation. In the event of malfunction, equipment is immediately taken out of service and only returned after thorough repair and safety verification.

Waste Disposal Protocols

We follow institutional and national guidelines for the disposal of chemical, biological, and sharps waste. Waste is categorized and treated appropriately, with hazardous materials being sterilized or neutralized before final disposal. All team members are trained in waste classification and handling, and we have established clear procedures for emergency waste management to ensure preparedness in case of accidental spills or exposure.