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Evaluation of the Biocontrol Potential of a Commercial Yeast Starter against Fuel-Ethanol Fermentation Contaminants
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Orientador(es)
Resumo(s)
Lactic acid bacteria (LAB) and Brettanomyces bruxellensis are the main contaminants of bioethanol fermentations. Those contaminations affect Saccharomyces cerevisiae performance and reduce ethanol yields and productivity, leading to important economic losses. Currently, chemical treatments such as acid washing and/or antibiotics are used to control those contaminants. However, these control measures carry environmental risks, and more environmentally friendly methods are required. Several S. cerevisiae wine strains were found to secrete antimicrobial peptides (AMPs) during alcoholic fermentation that are active against LAB and B. bruxellensis strains. Thus, in the present study, we investigated if the fuel-ethanol commercial starter S. cerevisiae Ethanol Red (ER) also secretes those AMPs and evaluated its biocontrol potential by performing alcoholic fermentations with mixed-cultures of ER and B. bruxellensis strains and growth assays of LAB in ER pre-fermented supernatants. Results showed that all B. bruxellensis strains were significantly inhibited by the presence of ER, although LAB strains were less sensitive to ER fermentation metabolites. Peptides secreted by ER during alcoholic fermentation were purified by gel-filtration chromatography, and a bioactive fraction was analyzed by ELISA and mass spectrometry. Results confirmed that ER secretes the AMPs previously identified. That bioactive fraction was used to determine minimal inhibitory concentrations (MICs) against several LAB and B. bruxellensis strains. MICs of 1–2 mg/mL were found for B. bruxellensis strains and above 2 mg/mL for LAB. Our study demonstrates that the AMPs secreted by ER can be used as a natural preservative in fuel-ethanol fermentations.
Descrição
Part of the research was carried out at the Biomass and Bioenergy Research Infrastructure (BBRI)-LISBOA-01-0145-FEDER-022059, supported by Operational Programme for Competitiveness and Internationalization (PORTUGAL2020), by Lisbon Portugal Regional Operational Programme (Lisboa 2020) and by North Portugal Regional Operational Programme (Norte 2020) under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF).
Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.
Palavras-chave
antimicrobial peptides bioethanol Brettanomyces bruxellensis glyceraldehyde 3-phosphate dehydrogenase lactic acid bacteria microbial contamination S. cerevisiae Food Science Biochemistry, Genetics and Molecular Biology (miscellaneous) Plant Science