Team:CIEI-China/Project/Design
The basic idea of our project was to transfer the salt resistant gene into microbes to improve their decomposition efficiency for food waste in high salinity environment.
In order to reach our goal, we need to consider the materials, including the carriers and the genes.
For carriers, we planned to select one particular kind of microbes from the common functional microbial community as an example. During our research, we discovered that the common microbes in food waste decomposition include yeasts, Lactobaillus, Azotobacter, silicate bacteria, Bacillus subtilis, and Bacillus Licheniformis, etc. (Zhao, 2009). Among various microbes utilized in waste disposal, yeasts have the characteristics of osmosis resistance, acid resistance, high metabolic rate and ability to degrade cellulose efficiently. Most importantly, yeasts can promote the hydrolysis of food waste, leading to its pivotal role in the anaerobic fermentation process due to the high moisture of food waste, which negatively affects the efficiency of microbes and results in prolonged food waste disposal process (Xu, 2014). Therefore, considering all the benefits of yeasts, we selected pichia pastoris, a member of the yeast community, as our carrier, since pichia pastoris is a type of common bacteria used in lab experiment.
For genes, we chose three salt resistant genes, gltB, ScTPS1, and SpTPS1, and inserted them into pichia pastoris separately, so the modified yeasts can produce glutamate or trehalose to improve their survivability and decomposition rate under high salinity. Among the three genes, we picked the one which helped the most in survivability when transgenic yeasts are cultured in hypersaline media. Finally, we add salt solution with different concentrations, which can simulate kitchen waste in most real-life conditions, in several culture dishes of pichia pastoris in order to test the strength of salt resistance of our genetically modified yeast.
Based on our research, the newly modified yeast can be applied to food waste disposal industries and restaurants to help improve the effectiveness of decomposition, recycle the nutrients, and hence save more energy on earth.
Our device
