Contamination control in corn mash fermentation using recombinant endolysin secreted by Saccharomyces cerevisiae

Authors: Lu, Shao; PATEL, MAULIK - Orise Fellow; Hector, Ronald; Bowman, Michael; Skory, Christopher

Submitted to: Corn Dry Milling Conference
Publication Type: Abstract Only
Publication Acceptance Date: 5/29/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: In 2023, the United States accounted for 53% of global bioethanol production, yielding 15.6 billion gallons. However, bioethanol fermentation is prone to contamination by lactic acid bacteria (LAB) that compete for nutrients, produce inhibitory byproducts, such as acetic and lactic acid, and decrease ethanol productivity by yeast. Current bacterial mitigation methods, including chemical cleaning (e.g., hop acid and chlorine dioxide) and antibiotic treatments, are often impractical or minimally effective. To address this challenge, we genetically engineered Saccharomyces cerevisiae, a bioethanol production yeast strain, with the ability to secrete a bacterial killing enzyme termed endolysin LysKB317. The secretion of endolysin by the yeast strain significantly reduced bacterial contamination (>100 bacteria/mL loss) and lowered acetic acid and lactic acid concentration levels by 73% and 67%, respectively when compared to the no treatment infection control. Moreover, ethanol production increased by 16.7%, and glucose utilization improved by 88.2% when compared to the infection control. This technology offers a cost-effective and sustainable alternative solution to bacterial contamination control without the use of antibiotics in bioethanol production.