In Situ Detoxification of the Fermentation Medium during γ-Decalactone Production with the Yeast Sporidiobolus salmonicolor

Abstract

γ‐Decalactone (γ‐C10) 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 β‐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. β‐cyclodextrins, which have a hydrophobic cavity that can trap molecules such as γ‐C10, 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 γ‐C10. For improvement of the lactone production, the oil trapping method seemed to be the best with the experimental conditions tested.