Plastics have long been an important type of wastes in human activity. A study from Hong Kong Environmental Protection Department stated that in 2021, about 20% from our municipal solid waste disposal are waste plastics, which are second largest components of municipal solid waste, followed by food waste.
Among them, per and polyfluoroalkyl substances (or PFAS) is one of the major sources causing heavy contamination of soil, surface water and ground water. PFAS is a large, complex group of synthetic chemicals that have been used in consumer products around the world since 1950s.
PFAS affect environment in several area, such as soil, surface and groundwater and surface water, air, and most importantly the wildlife deeply. Bioaccumulation of PAFS occurs along the food chain, and thus stays in the environment.
PFAS break down slowly, if people and animals are repeatedly exposed to them, blood levels of some PFAS can build up over time. Long-term exposure to PFAS results in certain medical conditions, such as kidney cancer and thyroid disease. They also affect human growth and development, as well as reproduction, thyroid, liver and immune function.
Concerns about the public health impact of PFAS have arisen for the following reasons, which can be concluded in a word "PACE":
Our aim is to speed up degradation of PFAS by omtimizing the activities of two enzymes which are responsible for degrading PFAS, namely lignin peroxidase (LiP) and manganese peroxidase (MnP).
LiP and MnP are naturally secreted by mushrooms. These enzymes work together to degrade PFAs by first converting chemical compounds from nature into reactive radicals, which then react with the PFAs.
Inspired by CUHK iGEM team, our project aims at promoting the degrading rate of PFAS. We aim to search for possibility in speeding up degradation process by conjugating each azide-modified oligonucleotide with corresponding engineered enzyme.
These two oligonucleotides are then bound with each other under complementary base pairing, connecting two conjugated products. A "Cascade Enzyme System" of LiP and MnP is then formed.
PFAs degradation performance could then be determined by qualitative or quantitative method.