Various chemical compounds, including surfactants, when introduced to culture media may increase the permeability of cellular membranes and thereby affect the quantity of metabolites excreted by cells. The aim of the present study was to evaluate the impact of detergents including Triton X-100, Span 20 and Tween 80 on erythritol production from glycerol by Yarrowia lipolytica Wratislavia K1 in a shake-flask experiment, batch and fed-batch cultures. When Span 20 was added to a fed-batch culture with glycerol as a carbon source (300 g L−1), erythritol production increased by 15% compared to the culture without the surfactant where it reached 142 g L−1 after 5 days, which corresponded to 0.47 g g−1 yield and productivity of 1.1 g L−1 h−1. Therefore, it was concluded that Span 20 considerably enhanced the production of this polyol from glycerol.

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With the problems related to chemical methods of pyruvic acid (PA) synthesis, a fast-growing interest has been observed in research aiming at reducing the production cost of PA by applying biotechnological methods. This study aimed to investigate the potential applicability of Yarrowia lipolytica Wratislavia 1.31 yeast strain for valorisation of pure and crude glycerol through the production of industrially desired PA. Conditions required for the effective PA biosynthesis, i.e., pH value, thiamine concentration, agitation, and substrate concentration, were examined in batch and fed-batch cultivation modes. The efficient production of PA occurred under the limitation of thiamine (1 µg L −1) and was stimulated by moderate pH (4.5) and agitation (800 rev min −1) of the culture. Under optimal conditions, Y. lipolytica Wratislavia 1.31 was able to produce 85.2 g L −1 of PA with volumetric productivity of 0.90 g L −1 h −1. The yield of PA biosynthesis reached a high level of 1.03 g g −1. Obtained results confirmed the aptitude of Y. lipolytica yeast to produce high amounts of PA from simple glycerol-containing media. Presented process was very promising and might be considered as an attractive alternative for currently used chemical methods of PA synthesis. Keywords Pyruvic acid production • α-ketoglutaric acid • Glycerol • Yarrowia lipolytica • Culture conditions Abbreviations X Biomass (g L −1) PA Pyruvic acid (g L −1) KGA α-ketoglutaric acid (g L −1) Y Pyruvic acid production yield (g g −1) Q Volumetric productivity of pyruvate (g L −1 h −1) q Specific production rate of pyruvic acid (g g −1 h −1) η PA Yield coefficient of PA production

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