Hydrophobins for Improved Plastics Binding and Bio-Deconstruction

Microplastic pollution is rapidly accumulating in the world, leading to significant environmental and human health issues. For example, plastic waste makes up 80% of all marine pollution. A surgery study with 200 people also noted that 60% of patients had microplastics in their main artery and were 4.5 times more likely to experience a heart attack, a stroke or death in the 34 months after the surgery. Current waste management methods such as mechanical or chemical recycling are inefficient and lack product specificity. Microbial degradation has been leveraged as a way to degrade plastics but falls short due to the poor access microbes have on the plastic. In this work, we utilize a strain of Aspergillus fumigatus to bind to microplastics and pull them out of the environment with nearly 100% recovery. We identified hydrophobin proteins as the predominant biomolecules driving efficient plastic binding flocculation. 7 different hydrophobin genes, RodA-RodF, were present in the yeast genome. RodA is reported as the most expressed hydrophobin responsible for cell wall surface hydrophobicity. By knocking out each gene individually then testing the plastic recovery, the RodA knockout resulted in significantly less plastic recovery. Therefore RodA is the main hydrophobin gene responsible for plastics binding and it can be used to subsequently improve plastic deconstruction. We are developing a proof-of-concept hydrophobin and plastic-oxidizing enzyme surface display system for improved plastic oxidation in Yarrowia lipolytica. This system can then be tied to a full bio-deconstruction cascade, allowing for efficient and sustainable plastics deconstruction.