Session: Presidential Symposium: Plastics and the Oceans: Chemistry for the Journey Ahead:

Nowadays, over 6,300 million tons of fossil-fuel plastic has been generated, with only 9% of it being recycled and 79% ending in landfills. Plastic persistence in the environment is causing serious environmental problem such as white pollution, entering the food chain and threatening the life of animals and plants. As the demand of plastic production keeps increasing, expected to be 12,000 million tons by 2050, there is a need to promote alternative materials for biodegradable plastic production. Polyhydroxyalkanoate (PHA) is a biopolymer which has similar properties as fossil-fuel based plastic but also has capacity to completely biodegrade in the environment condition. This project aims to develop a new process to produce bioplastic PHA using activated sludge from wastewater. In this project, PHA is synthesized by endogenous microorganisms found in wastewater activated sludge. 13 different sludge samples were collected from 6 wastewater treatment plants (WWTP) from the New York City metropolitan area. The sludge samples are characterized for PHA synthesis capacity (microbial community diversity), total suspended solid (TSS), volatile fatty acids (VFAs), and PHA content. Our preliminary results indicate that all activated sludge samples have the capacity of PHA generation. Microbial community analysis shows that PHA-production affiliated microorganisms account for up to 29.2% and important PHA-accumulating organisms are up to 4.8%. PHA concentration in the untreated sludge samples is relatively high, with up to 20% w/w as PHA and 8% w/w as PHB. Current efforts are focused on developing an enrichment process for PHA accumulating microorganisms through feast-famine cycles. The efficiency of PHA production is being evaluated with changing operational parameters such as pH, temperature, retention time absorbent, and bacterial community. The produced PHA will be analyzed for the chemical, mechanical and thermal properties to identify the PHA main functional groups which affect the main properties of the bioplastic. This study is expected to enhance the PHA production by using waste and estimate the properties of mixture culture produced PHA.

BO DENG

Ph.D. Candidate, New Jersey Institute of Technology

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