Economic biodiesel production using algal residue as substrate of lipid producing yeast Cryptococcus curvatus

Abstract

Oleaginous microbes which are surely one sustainable way of producing lipid in absolute need of reducing the substrate cost for the commercialization. In this study, algal biomass residue, which is a waste generated after the production of algae-based biofuel, was investigated for its possibility as a cheap feedstock using our newly isolated yeast Cryptococcus curvatus. To make the algae biomass bioavailable, hydrodynamic cavitation (HC) was employed as a pretreatment means, whose optimal treatment condition was systematically set up using Response Surface Methodology (RSM). The optimal condition was HC pretreatment time of 6.88 min at pH 9.47. When used the pretreated microalgae, the C curvatus can grow with growth rate of 0.584/h, biomass reached to 7.47 g/L in a day, and lipid productivity (1.5 g/L/d) was better than defined medium using commercial chemicals.