Microbial valorization of food waste into biosurfactants: innovations and application in food industry

Chemical surfactants are inexpensive but non-biodegradable, persisting in the environment and causing ecological contamination and potential health risks. In contrast, biosurfactants are biodegradable, sustainable, and exhibit low toxicity, making them promising alternatives. However, high production cost of biosurfactant remains a major barrier to their widespread adoption. This review critically examines the potential of utilizing food waste substrates, such as fruit and vegetable waste, frying oil, and expired dairy products, to reduce biosurfactant production costs by supporting the growth and metabolism of biosurfactant-producing microbes. Specifically, we highlight the biosurfactant-producing capabilities of Lactic acid bacteria (LAB), Bacillus spp., and yeast, with emphasis on their substrate specificity, biosurfactant yield and extraction methods. The review further explores the impact of different substrate types on microbial metabolism, along with the pretreatment processes required to enhance substrate utilization efficiency. Moreover, the review examines the role of genetic engineering and fermentation process optimization in improving biosurfactant yields and production efficiency. Additionally, the review highlights the emulsifying properties, functional properties of biosurfactants and examines their current and potential applications in the food industry. Leveraging food waste, such as molasses, soybean oil, and soybean meal, offers a sustainable solution to reduce production costs and address challenges in the downstream processing of biosurfactants.