The purpose of this study was to evaluate the ability of five strains of yeasts Yarrowia lipolytica JII1a, JII1b, JII1c, PII6a, PII6b, isolated from Polish mould cheese, to secrete extracellular proteolytic and lipolytic enzymes. After their cultivation for 48 hours in media containing different carbon and nitrogen sources the level of population growth as well as the activities of proteolitic enzymes (at pH 3,0 and 7,5 against hemoglobin and casein, respectively) and lipolytic enzymes (against butter oil and tributyrine) were determined. It was shown that investigated strains of Y. lipolytica exhibited different growth and enzyme biosynthesis pattern depending on the carbon and nitrogen source present in medium. Populations of all studied strains reached the level of 1,5-2,1 ∙ 10⁸ cells mL^-1 in medium containing glucose and casein as the carbon and nitrogen sources, respectively. Substitution of glucose by plant oils resulted in decrease of their growth. Similar effect was observed when casein was substituted by more simple nitrogen sources. The exception was strain JII1 c, which growth was not affected by nitrogen component replacement. The changes in composition of growth medium influenced on the biosynthesis level of hydrolytic enzymes. The presence of glucose stimulated the production of extracellular aspartic proteinase. Also whey proteins favoured the biosynthesis of this proteinase. Whereas applying of the olive oil enhanced biosynthesis of serine proteinase. The presence of plant oils, including olive oil, in growth medium promoted the secretion of lipolytic enzymes.

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