In Situ Detoxification of the Fermentation Medium during (gamma)-Decalactone Production with the Yeast Sporidiobolus salmonicolor

(gamma)-Decalactone ((gamma)-C(andis)10) is known to be highly toxic for the microorganims used for its production. In this work, three techniques were studied in order to overcome this toxicity during a bioconversion process using ricinoleic acid as precursor of the lactone: in situ trapping in oily phases, in porous hydrophobic sorbents and in (beta)-cyclodextrins. Oily phases added to the media (olive, Miglyol, tributyrin, and paraffin) had a protective effect on Sp. salmonicolor, and they improved the lactone production.(beta)-cyclodextrins, which have a hydrophobic cavity that can trap molecules such as (gamma)-C(andis)10, have been used to protect the yeasts. The results showed insufficient preservation of cell viability. Some sorbents (activated carbon and polystyrene-based sorbents) were successfully tested during bioconversion. In all cases viability exceeded the reference one. Nevertheless the aroma production was 30% lower than the reference. All of these solutions led to some enhancement of the cell viability during bioconversion of methyl ricinoleate to (gamma)-C(andis)10 For improvement of the lactone production, the oil trapping method seemed to be the best with the experimental conditions tested.