Comparison of gamma-decalactone biosynthesis by yeast Yarrowia lipolytica MTLY40-2p and W29 in batch-cultures

Gamma-decalactone is an interesting flavuring compound with an intense oily-peachy aroma. It is commonly used in food and cosmetic industry. Biotechnological methods of its synthesis are based on the processes of fatty acid degradation, mainly ricinoleic acid, which is the main component of castor oil. The aim of this study was to compare the productivity of gamma-decalactone in batch cultures of two strains of Yarrowia lipolytica, wild strain W29 and its derived mutant MTLY40-2p, grown in flasks and a bioreactor. We analyzed the concentration of gamma-decalactone in the aqueous and oil phase, the optical density of the medium, the yield of yeast dry matter and the particle size distribution in the particular media. The modified strain had a higher aroma synthesis capacity. This strain grown in flasks produced thrice as much gamma-decalactone (5.5 ± 0.16 g/L) as compared to the wild-type strain (1.8 ± 0.03 g/L). During the 7-day biotransformation, the mutant strain did not have the ability to degrade gamma-decalactone, whereas in the biotransformation using the wild-type strain, reutilization was observed after the third day. Regardless of the type of culture, larger amounts of gamma-decalactone were accumulated in the lipid phase. Cultivation in a bioreactor resulted in a lower biomass yield and a lower concentration of lactone compared to flask culture, regardless of the strain used. The MTLY40-2p strain grew in mycelium form and tended to aggregate cells.