Increase in lipids production by Pichia angusta DL-1 utilizing the chemostat under double limitation of heterologous nutrients

Abstract

For many years there has been industrial interest to produce microbial oils through oleaginous microorganisms. Its fatty acids composition is similar to vegetable oils, so that the use of microbial polyunsaturated fatty acids has been very important in animal nutrition and is currently considered the potential feedstock for biodiesel, therefore any significant improvement in the process of lipid synthesis will reduce costs of production at industrial level. We investigated the use chemostat under different heterologous double nutrient limitations, that is, nutrients that meet different physiological requirements, in order to achieve a higher production lipid accumulation in oleaginous yeast. We used Pichia angusta DL-1 grown in a chemostat under carbon/phosphorus, carbon/magnesium, nitrogen/phosphorus and nitrogen/magnesium double limitations at five different dilution rates. The largest accumulation of lipids occurred under nitrogen/phosphorus limitation at a dilution rate of 0.03h−1 and carbon/magnesium limitation at a dilution rate of 0.07h−1. At that condition lipid content was twice the one obtained in batch culture and 15% larger than under simple limitation. Finally, under carbon/magnesium limitation the highest lipid productivity (0.011g/Lh) was obtained with a cell productivity of 0.033g/Lh.