Bioconversion of drimenol into 3 beta-hydroxydrimanes by Aspergillus niger. Effect of culture additives.

The bioconversion of (-)-drimenol [1] and drimenyl acetate [2] into the corresponding 3 beta-hydroxydrimanes by Aspergillus niger in agitated liquid cultures was investigated. Initial hydroxylation yields of 2% and 10%, respectively, were obtained. However, drimenyl acetate hydroxylation increased to 18% when Carbopol-934 was added. The highest transformation yield (33%) was reached when an inclusion complex of drimenyl acetate to beta-cyclodextrin (1:1 w/w) was added to the cultures, after 48 h of cultivation. The effect on growth and transformation yields of both additives is discussed.