05/02/2025
By Danielle Fretwell

The Francis College of Engineering, Department of Chemical Engineering, invites you to attend a Doctoral Dissertation Proposal defense by Jiansong Qin on: "Metabolic Engineering of Yarrowia lipolytica for High-Yield Production of Omega-3 Eicosapentaenoic Acid (EPA) from Waste Cooking Oil.”

Candidate Name: Jiansong Qin
Degree: Doctoral
Defense Date: Monday, May 12, 2025
Time: 2 - 3 p.m.
Location: Perry 315

Committee:

  • Advisor: Dongming Xie, Associate Professor, Chemical Engineering Department, UMass Lowell
  • Hal Alper, Professor, Chemical Engineering Department, The University of Texas at Austin
  • Carl Lawton, Associate Professor, Chemical Engineering Department, UMass Lowell
  • Seongkyu Yoon, Professor, Chemical Engineering Department, UMass Lowell
  • Quinn Zhu, Technical Fellow, International Flavors & Fragrances

Abstract:
Omega-3 fatty acids, particularly eicosapentaenoic acid (EPA), offer significant health benefits, but current sources like fish oil face sustainability and quality challenges. Engineered microbial platforms present a promising alternative. This research aims to develop a sustainable and efficient biomanufacturing platform using the oleaginous yeast Yarrowia lipolytica strain Y8412 to convert waste cooking oil (WCO), an abundant and low-cost feedstock, into high-value EPA. The project integrates bioprocess optimization with metabolic and protein engineering strategies. Key objectives include optimizing co-fermentation of glucose and WCO, overcoming free fatty acid (FFAs) toxicity associated with WCO feeding by re-engineering lipid synthesis and degradation pathways, enhancing the efficiency of the engineered EPA synthesis pathway through targeted gene overexpression, optimizing promoter strength, and improving the availability and utilization of reducing power (NADPH/NADH) for fatty acid desaturation. Preliminary results demonstrate that while WCO co-feeding increases total lipid accumulation, it also leads to detrimental FFAs buildup and reduced EPA percentage. However, engineering strategies, such as deleting the TGL4 lipase gene, significantly mitigated FFAs toxicity, enhanced biomass and lipid yields, and substantially increased total EPA production compared to both the parent strain using WCO and the parent strain using glucose alone. Further engineering targeting precursor supply, pathway enzyme expression, lipid turnover, and redox balance shows potential for additional improvements. This research provides a pathway toward sustainable, high-yield EPA production from waste streams, addressing market demands and environmental concerns.