Engineering antimicrobial strains of saccharomyces cerevisiae as industrial platform for non-sterile bioprocesses
type: CreativeWork
description: Microbial contamination is a major challenge in fuel ethanol facilities, especially during the fermentation stage. Bacterial contaminants compete with yeast for fermentable sugars and nutrients, which obstructs starch to ethanol conversion. This leads to a reduction in ethanol yield. At large production scales, prior sterilization of the feedstocks is economically unfeasible. Therefore, antibiotic supplementation is common practice to limit the growth of contaminating bacteria. In addition to the high cost of the antibiotics, concerns and evidence are mounting that antibiotic use in non-clinical settings is driving the emergence of drug resistant microbes. This study focused on heterologous expression of antimicrobial peptides (AMP) as an alternative strategy for combating microbial contamination. This work aimed to engineer an industrial Saccharomyces cerevisiae strain that produces AMPs active against lactic acid bacteria and Enterobacteriaceae which are some of the main bacterial contaminants found in industrial biofuel fermenters. Seven candidate AMPs were selected from curated online databases, and their amino acid sequence was analyzed using bioinformatic tools. AlphaFold, Clustal Omega, and SNAP2 were used to predict AMP tertiary structures, construct a phylogenetic tree, and analyse mutation effects, respectively.
abstract: Microbial contamination is a major challenge in fuel ethanol facilities, especially during the fermentation stage. Bacterial contaminants compete with yeast for fermentable sugars and nutrients, which obstructs starch to ethanol conversion. This leads to a reduction in ethanol yield. At large production scales, prior sterilization of the feedstocks is economically unfeasible. Therefore, antibiotic supplementation is common practice to limit the growth of contaminating bacteria. In addition to the high cost of the antibiotics, concerns and evidence are mounting that antibiotic use in non-clinical settings is driving the emergence of drug resistant microbes. This study focused on heterologous expression of antimicrobial peptides (AMP) as an alternative strategy for combating microbial contamination. This work aimed to engineer an industrial Saccharomyces cerevisiae strain that produces AMPs active against lactic acid bacteria and Enterobacteriaceae which are some of the main bacterial contaminants found in industrial biofuel fermenters. Seven candidate AMPs were selected from curated online databases, and their amino acid sequence was analyzed using bioinformatic tools. AlphaFold, Clustal Omega, and SNAP2 were used to predict AMP tertiary structures, construct a phylogenetic tree, and analyse mutation effects, respectively.
author: Van Lill, Gert Rutger
keywords: Microbial Contamination, Challenge, Fuel Ethanol, Fermentation Stage, Bacterial Contaminants
license: https://uwcscholar.uwc.ac.za/bitstreams/8a3104f5-c333-4b0e-8807-88d17a46d702/download
date published: 2023
date modified: 2026-07-24T06:00:52Z
provider: University of the Western Cape
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of the Western Cape