Optimization of trace elements in purified glycerol for microbial lipid and citric acid production by Yarrowia lipolytica SKY7

Abstract

Purified glycerol obtained after acid treatment of crude glycerol solution was used as the carbon source for lipid and citric acid production using Y. lipolytica SKY7. Although purified glycerol was high in phosphorus, it was important to investigate the impact of fortification of trace elements in the medium on cell growth, lipid and citric acid (CA) production. When all the trace elements (including phosphates and sulfates) required for growth and lipid production were added to the purified glycerol medium, high biomass (51.67 g/L) and lipid concentration (19.47 g/L) were observed at 96 h of fed-batch fermentation with low CA concentration of 5.42 g/L. The purified glycerol medium without additional trace elements gave low biomass (27.67 g/L), lipid concentration (9.35 g/L) at 80 h of fed-batch fermentation, but gave high CA concentration (24.51 g/L). When purified glycerol was provided with only sulfates or all elements except KH₂PO₄, low biomass (32.59 g/L and 38.52 g/L) and citric acid concentration (1 g/L and 2.42 g/L) were obtained at 96 h.

Funding

Natural Sciences and Engineering Research Council of Canada,(A4984)