As the population of the earth continues to grow, more waste is ending up in landfills, with many of the items being compostable food waste. Food waste disposal in landfills has many environmental consequences, primarily the greenhouse gases emitted during anaerobic decomposition. Although food waste disposal services are available, such services release methane and are not economically feasible, and residential and industrial composting methods are oftentimes not readily available. We propose a system that employs engineered enzymes that breaks down food waste in a more accessible small-scale closed container system in any climate, ensuring that unsafe chemicals produced during the composting do not enter the environment. Our aim is to increase the speed of decomposition of homogalacturonan, a common form of pectin, using the enzymes pelB pelC and pnl in an engineered pectin-degradation catalyst. This project will address a local problem within the Lethbridge community and a worldwide issue.
What is tPectinACE?
Inside most produce is Pectin, a biomolecule that provides our food with a backbone and structure. Our goal is to accelerate how fast Pectin is degraded which will then make composting faster. The foundation of our project revolves around the breakdown of Homogalacturonan, HG, which is a type of pectin that is the simplest and most common. We will use enzymes from the Paenibacillus amylolyticus organism because they follow the natural degradation pathway for HG. This is because all three enzymes, PelB, PelC and PnL have wide substrate range that is necessary to breakdown both the methylated and unmethylated regions on HG without having to break down the HG first. We chose these enzymes because together they all work with each other the best compared to other enzymes from the same organism, and they all perform the job we need to be done on the HG to have an efficient system.
So far, there are two possible methods that we can use to deliver our system as both will work superbly and effectively. One way is to engineer a HG degradation pathway into a microbe and then applying that lysate to the compost or by purifying the three enzymes to create a lyophilized powder to be administered to the compost. There are two possible hosts for our system. E. coli the most widely used organism in synthetic biology, due to its rapid growth and high yield, provides us with a model organism to study bacterial metabolic pathways. E. coli also does not contain any pectin-degrading enzyme, making it a great candidate to characterize and validate our HG degrading system. Our second option is the Bacillus subtilis because it is classified as safe and not considered pathogenic or endotoxic to humans. Another reason as to why it is a contender is that some of its strains can utilize polysaccharides such as pectin so there is a possibility that pectinase may be present in its genome. Both these hosts are wonderful possibilities to deliver our system and have factors that are beneficial to the efficiency of our system.