Conversion of <i>Arthrospira platensis</i> Biomass into Microbial Lipids by the Oleaginous Yeast <i>Cryptococcus curvatus</i>

Abstract

Microbial lipids with fatty acid compositional profiles similar to vegetable oils are of great potential for the production of biofuels and oleochemicals. However, the costs of microbial lipids remain prohibitively high for broader applications. Microalgae known as the third-generation biomass resources may be explored to reduce the feedstock costs of lipid production. Here, hydrolysates of the microalga Arthrospira platensis were converted into lipids by the oleaginous yeast Cryptococcus curvatus ATCC 20509. Results indicated that hydrothermal pretreatment at 120 °C followed by enzymatic hydrolysis led to recovery of up to 97% total reducing sugar from microalgal biomass. While the as-prepared hydrolysates were ineffective for lipid production due to its nitrogen-rich nature, a high lipid content of 64.5% and a lipid yield of 0.233 g/g were obtained upon phosphate removal with calcium hydroxide. The lipid samples were found similar to palm oils in terms of fatty acid compositional profiles. This work demonstrated that A. platensis biomass can be readily converted into hydrolysates for high-yield lipid production, suggesting an alternative feedstock to cellulosic residues for microbial lipid technology and biorefinery.