Researcher(s)
- Agni Miraji-Khot, Chemical Engineering, University of Delaware
Faculty Mentor(s)
- Mark Blenner, Chemical Engineering, University of Delaware
Abstract
One of the major challenges in plastic waste management is the lack of an economical recycling solution for polyolefins, the most abundant class of plastics, such as polyethylene (PE), polypropylene (PP), and polystyrene (PS). Their strong carbon-carbon backbone makes them difficult to deconstruct, often requiring expensive catalysts and energy intensive methods. Two challenges to polyolefin bio-deconstruction: it is difficult to bind to the hydrophobic surface of the plastic, and deconstruction is a multi-step process which must be initiated with oxidation. Therefore, we study the gut microbiota of yellow mealworm larvae, which are able to overcome these challenges and rapidly (~20 days) deconstruct low-density polyethylene (LDPE), a common type of PE. As the gut is anticipated to be rich in plastic-degrading enzymes, we isolated microorganisms with the ability to either bind or oxidize PE.
An essential part of the polyolefin deconstruction process for bacteria is being able to form a biofilm on the surface. Almost every report of microbial activity with polyolefins as a substrate occurs after biofilm formation. My project for the summer is determining whether the bacterial isolates from the yellow mealworm gut microbiome are capable of biofilm formation on LDPE films.
To quantify the formation of biofilms, I made use of two different techniques: crystal violet staining and colony forming unit (CFU) quantification. After detaching the biofilm from the surface of LDPE through agitation with a surfactant, crystal violet staining was performed to measure the biomass of biofilm formed on the LDPE. At the same time, CFU quantification was performed to determine the viability of the cells on the biofilm. Using these two methods, the “quality” and “quantity” of the biofilm can be effectively determined.