Peptone as a nitrogen source for erythritol production from glycerol by Yarrowia lipolytica yeast

Erythritol is a compound widely distributed in nature. It found application in medicine, cosmetics, chemical and food industry. It has 60–80% sweetness in comparison to sucrose, very low energy value (~0.2 kcal/g), is non-cariogenic and free of gastric side-eff ects. This sugar alcohol is commercially produced in microbiological processes using glucose and sucrose. Glycerol, which is produced in large amounts by biodiesel industry, can be used as alternative substrate for the production of erythritol by Yarrowia lipolytica yeast. The aim of the study was to examine the impact of peptone on erythritol production from glycerol by Wratislavia K1 strain of Y. lipolytica. In the 10-days shake-fl asks experiment the peptone concentration of 1–12 g/L were examined. Pure glycerol (98% wt/wt) was used as carbon and energy source. The media were supplemented with 2.5% and 5% of NaCl. The results showed that peptone could be used as nitrogen source in erythritol biosynthesis from glycerol by Y. lipolytica yeast. The best results were achieved with 2 g/L of peptone and 5% of NaCl, where yeast produced 18.2 g/L of erythritol, corresponding to 0.23 g/g yield, 0.11 g/(Lh) volumetric productivity and specifi c production rate of 0.010 g/(gh). In this conditions minimal level of of by-products was formed — arabitol production was not observed while mannitol, citric acids and α-ketoglutaric acid did not exceed 0.4, 4.4 and 2.0 g/L, respectively.