An isolation medium for gamma-linolenic acid producing mucoralean fungi

An isolation medium was developed to isolate acetate tolerant mucoralean fungi capable of producing gamma-linolenic acid (18:3n-6) from sodium acetate as carbon source. Ir was found that acetate tolerant mucoralean fungi, capable of growing on a medium containing 20 g/l acetate, are associated mainly with the genera Actinomucor, Mucor and Thamnostylum. Acetate tolerance, however, may vary within species. Thirty strains were isolated from leaf litter and compost rich soil from different geographical areas in southern Africa. Most of these isolates were representatives of the biotechnologically important species Mucor circinelloides. The isolates were then screened for the ability to accumulate lipids rich in 18:3n-6. It was found that the isolates compared favourably with strains representing species that is known for substantial amounts of 18:3n-6 accumulation.