Exploring lipopeptide biosurfactants as natural preservatives for bakery products

Serrão Lopes de Sousa, A. R. (2025) Exploring lipopeptide biosurfactants as natural preservatives for bakery products. PhD thesis, University of Reading. doi: 10.48683/1926.00123163

Abstract/Summary

Microbial spoilage, primarily caused by fungal contamination, poses a significant challenge to the safety, shelf-life, and sustainability of bakery products. This research investigates lipopeptide biosurfactants, specifically mycosubtilin, as natural preservatives to address these challenges and meet consumer demand for “clean label” solutions. Lipopeptides, recognised for their antifungal properties, were screened via in vitro microdilution assays to determine antifungal activity and minimum inhibitory concentrations against key spoilage fungi, including Aspergillus niger and Penicillium paneum. Thermal stability tests confirmed their resilience to baking temperatures, and challenge tests demonstrated that mycosubtilin significantly extended the shelf-life of inoculated bread slices. Further experiments examined the influence of bread matrices and individual ingredients, revealing that while mycosubtilin retains its antifungal activity in complex bread systems, the presence of oil and starch reduced its efficacy. Transcriptomic analysis of A. niger and Saccharomyces cerevisiae uncovered molecular pathways targeted by mycosubtilin, highlighting its stronger inhibition of spoilage fungi while preserving yeast functionality essential for bread fermentation. To evaluate resistance potential, whole-genome sequencing of resistant fungal and yeast strains was performed. Results showed limited adaptation in spoilage fungi and a moderate increase in yeast tolerance, supporting the industrial feasibility of mycosubtilin. This study demonstrates mycosubtilin’s robust antifungal activity, thermal stability, and compatibility with bakery products, offering an effective and sustainable alternative to synthetic preservatives. By integrating fundamental and applied research, this work advances the potential adoption of lipopeptide biosurfactants, paving the way for cleaner, safer, and more sustainable preservation strategies in the bakery industry.

Item Type	Thesis (PhD)
URI	https://centaur.reading.ac.uk/id/eprint/123163
Identification Number/DOI	10.48683/1926.00123163
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Food and Nutritional Sciences
Date on Title Page	December 2024
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