A novel lipolytic yeast Meyerozyma guilliermondii: Efficient and low-cost production of acid and promising feed lipase using cheese whey

Abstract

Cheese whey is a by-product of the dairy industry that is generated in large quantities. It is considered the main pollutant in dairy wastewaters due to its high organic load. The aim of this paper was to produce lipases using cheese whey as the sole nutrient source. Yeasts isolated from slaughterhouse fridge effluent and oil mill effluent were screened for lipolytic activities. The lipase activity of the target yeast strain was increased by improving the culture conditions using a statistical design and the lipase activity was biochemically characterized. Among 25 yeasts, the L1 strain, identified by molecular markers as Meyerozyma guilliermondii, was selected as a good lipase producer. The best results were obtained when M. guilliermondii was grown in 2.0% of cheese whey at pH 4.0 for 24 h. Under these optimal conditions, a 6.7-fold increase of lipase production was achieved, corresponding to the production of 285.82 U mL−1, which is higher than others reported in the literature. Biochemical characterization revealed that M. guilliermondii lipase was more active and stable at 35–40 °C and in acidic conditions (pH 2.5–5.5). It also exhibited remarkable stability in organic solvents, especially those of a hydrophobic nature and excellent tolerance to digestive components. The novel isolate M. guilliermondii showed potential for use in feed industry thank to its ability to produce acid lipases efficiently and at a low cost using an abundant and polluting waste material.