This work demonstrates the ability of the yeast Yarrowia lipolytica cultivated on biodiesel waste to synthesize α-ketoglutaric acid with a minimal content of pyruvic acid as the main byproduct. The key factor promoting the microbial production of α-ketoglutaric acid from the waste is a strong deficiency of thiamine in the cultivation medium. The production of α-ketoglutaric acid by the yeast can be regulated by changing the concentration of nitrogen, iron, zinc, copper, and manganese in the medium, as well as by pH medium and the aeration rate. The optimization of these parameters in flask experiments allowed us to increase the concentration of α-ketoglutaric acid in the medium by 2.6 times and to shift the α-ketoglutaric acid/pyruvic acid ratio from 5:1 to 30:1. During cultivation in a fermentor under optimized conditions, Y. lipolytica produced 80.4g/L α-ketoglutaric acid with a process selectivity of 96.7% and the product yield (YKGA) equal to 1.01g/g. KEY POINTS: • α-Ketoglutaric acid is commercially important biotechnological product. • Biosynthesis of α-ketoglutaric acid from biodiesel waste. • Optimization of cultivation medium and nutrition medium.
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