Overview
Our project, POLYGONE, targets marine ester plastic pollution. By analyzing the entire life cycle of polyester plastics, we propose solutions for their production and microplastics disposal. We develop a marine-derived ester hydrolase with broad substrate spectrum, high activity, and high thermal stability. We immobilize it using a calcium carbonate and silica complex, an inorganic nanomaterial, and incorporate it into the plastics production process to achieve environmental degradation of polyester plastics. We also develop an E. coli co-expression system that displays the ester hydrolase and an adhesion protein on its surface, effectively degrading polyester microplastics in aquatic environments. Our ultimate goal is to apply this entire project to both the marine environment and human society. During the design of this project, we considered the potential hazards of environmental release of our products and designed appropriate experiments to test their safety. This page provides a comprehensive overview of the safety and reliability of our project.
Project safety
Our project design places great emphasis on safety. This year, our project focused on the design, expression, and enrichment of enzymes for biodegradation, so we carefully considered biosafety from three perspectives: chassis selection, enzyme safety, and degradation system.
1. Safety of choosing chassis
For our project, we selected Escherichia coli DH5α and BL21 (DE3) as the chassis strains. Both strains are well-established and commonly used in laboratory settings, classified as Biosafety Level 1 (BSL-1), and widely used in biocatalysis and protein expression research. According to the "Regulations on Biosafety Management of Pathogenic Microbiological Laboratories," BSL-1 microorganisms are non-pathogenic to healthy adults. This project poses no risk to individuals or the environment, and no other organisms are used.
2. Safety of enzyme design
All proteins expressed in our project are hydrolytic enzymes that are widely used in academic and industrial research, and are known to be harmless to humans. Based on current scientific knowledge, these proteins and the plasmids used in our system do not present any harmful effects to humans or other organisms. Our design does not include any toxic factors, antibiotic resistance beyond common laboratory use, or elements that could pose biosafety concerns.
3. Safety of the Degrading System
Our degrading system is based on a dual-anchoring surface display strategy, where adhesion proteins and ester hydrolases are anchored on the surface of E. coli. Importantly, we did not design living bacteria to be released into the environment. Instead, all engineered cells will be treated with chemical agents to ensure cell death before application. In this way, the degrading device will only function through surface-displayed enzymes, acting as a whole-cell catalyst without viable microorganisms.
For detecting degradation products such as terephthalic acid (TPA), we currently rely on chemical analytical methods in the laboratory. In the future, we plan to expand our system by engineering a TPA-responsive biosensor strain with additional safety features, such as salt- and oxygen-sensitive kill switches, to ensure self-termination in case of accidental release. This will allow us to integrate both degradation and detection functions into a single biological system while maintaining strict biosafety standards.
Lab safety
General Safety Principles
Throughout our experiments, we place the highest priority on the safety of both personnel and the environment. Before beginning any laboratory work, all members underwent a two-month comprehensive training program covering laboratory safety guidelines and fundamental experimental skills.
Once in the lab, every member is required to strictly follow established regulations, adhere to standard operating procedures, and maintain a rigorous and cautious attitude to ensure the safety and reliability of our work.
Personal Protective Equipment (PPE)
Before entering the laboratory, all personnel are required to wear appropriate PPE, including lab coats, gloves, masks, and protective goggles when necessary. PPE serves as the first line of defense against biological and chemical risks.
Laboratory Conduct
Non-experimental activities such as eating, drinking, or smoking are strictly prohibited inside the laboratory. Work and rest areas are clearly separated to prevent cross-contamination. After each experiment, benches, tools, and instruments must be disinfected and restored to their original condition.
Equipment and Chemical Safety
Laboratory equipment must be used in accordance with operating instructions, with regular inspections and maintenance to ensure reliable performance. Chemicals are stored based on classification, with clear labels. Volatile or irritating reagents must be handled in fume hoods.
Project-Specific Safety
Our project requires handling microorganisms and experimental materials under strict biosafety protocols. All microbial operations are carried out in designated laboratory areas with appropriate containment facilities. Team members must wear gloves, masks, and other PPE when performing related tasks to minimize the risk of exposure.
To ensure both researcher safety and experimental sterility, all wet-lab operations involving microbial transformation, spread plating, and colony picking were conducted under a laminar flow hood.
Experimental cultures are maintained in controlled incubators to ensure both research integrity and laboratory safety.
Waste Management
Waste management is a critical component of laboratory safety. We strictly follow the laboratory safety regulations, categorizing biological and chemical waste for proper disposal. Biological waste is sterilized before being placed in designated waste containers and handled by qualified agencies in accordance with national standards to prevent environmental contamination.
Emergency Preparedness
The laboratory is equipped with fire extinguishers, fire blankets, emergency showers, and eyewash stations. Team members receive training in emergency procedures, including responses to chemical leaks, biological spills, and fire incidents. Clear evacuation routes and regular drills ensure that personnel can act swiftly and effectively in emergencies.