The presence of selected dehydrogenases, including alcohol dehydrogenase (ADH-YL) and aldehyde dehydrogenase (ALDH-YL), in Yarrowia lipolytica JMY 861, and their potential role in the synthesis of flavor compounds were investigated. The experimental findings showed that using reduced form of nicotinamide adenine dinucleotide (NADH) as cofactor, the ADH-YL activity in-vitro was 6-fold higher than that with reduced form of nicotinamide adenine dinucleotide phosphate (NADPH); however, the results indicated the absence of any ALDH-YL activity. The in-situ reduction of hexanal into n-hexanol was found to be instantaneous; however, when the yeast cells suspension was diluted by 150-time, the initial relative hexanal concentration was increased by 84.1%. Using the diluted yeast cells suspension, the in-situ hexanal reduction reaction was achieved within 70 min of reaction, with a 95.4% relative n-hexanol concentration. The in-situ relative n-hexanol concentration decreased steadily with a concomitant increase in the hexanal concentration. The optimum pH of 6.7 for the biomass production of Y. lipolytica was shown to favor the hexanal reduction over the n-hexanol oxidation. The chromatographic analyses indicated the conversion, in-situ, of linoleic acid hydroperoxides (HPODs) into volatile C6-compounds, mainly 2-hexanone, hexanal, 3-hexanol and 2-hexenol, after 60 min of HPODs addition to the yeast cells suspension.

Role of selected microbial dehydrogenases in the synthesis of flavor compounds

251st National Meeting (2016)

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