Enhanced production of microbial lipids from waste office paper by the oleaginous yeast Cryptococcus curvatus

Waste paper has a potential to serve as renewable feedstock for the biorefineries of fuels, chemicals and materials due to rich in cellulose and its abundance at low cost. In the present study, pretreated waste office paper (WOP) was enzymatically hydrolysed and used for lipid production by Cryptococcus curvatus. The results suggested that the WOP hydrolysate supplemented with ammonium sulphate (2 g/L) and yeast extract (0.5 g/L) as nitrogen source at a C/N ratio of 80 were the most suitable for high yield of lipids. The biomass, lipid yield, lipid content and lipid coefficient achieved from batch cultivation of C. curvatus using untreated and pretreated WOP hydrolysates were 6.32 and 15.20 g/L, 1.39 and 5.75 g/L, 22 and 37.8%, and 99.9 and 234.6 mg/g sugar with the productivity of 0.02 and 0.08 g/L/h, respectively. The fatty acid profile of the lipids indicated that the oleic acid was the major fatty acid followed by palmitic acid, stearic acid and linoleic acid which is quite similar to plant/vegetable oils. Thus, the results suggested that the waste office paper could be an alternative feedstock for production of microbial lipids for biodiesel.