ELECTROACTIVITY OF YARROWIA LIPOLYTICA AND BIOPROCESS IMPROVEMENT

Abstract

Electrofermentation is known to mitigate redox imbalance in anaerobic growth, thus increasing growth and key metabolite production in yeast. In the first part of this work, I investigated growth, biofilm formation, and oil degradation under electrofermentation conditions of Yarrowia lipolytica through laboratory-scale bioelectrochemical cells. Two commonly used redox mediators, 2-hydroxy-1,4-naphthoquinone (2-HNQ) and potassium ferricyanide (K3[Fe(CN)6]) were tested to enhance the bio-electrochemical process. Results show that K3[Fe(CN)6] leads to better planktonic growth and biofilm formation compared to 2-HNQ. In the second part of the thesis, I investigated the possibility of using sunflower oil as an additional carbon source in a laboratory-scale electrofermentation process, to stimulate lipase production, a key group of enzymes used in the biofuel production and upcycling of waste oil. While I could not directly measure lipase expression, the electrofermentation experiments resulted in approximately 47 % higher cumulative charge output in presence of 5% of sunflower oil, suggesting that electrofermentation increases lipase production and oil metabolism. This work lay the basis for the development of an efficient waste oil degradation process under electrofermentation conditions.