LAUSR

Abstract This study explored an integrated proposal of using dewatered sludge to prepare media for Cryptococcus curvatus ATCC 20509 for accumulation of microbial lipids. A volatile fatty acids (VFAs)-containing solution produced by thermal alkaline pretreatment and anaerobic fermentation was used as the cultivation media. Combined conditioning processes including coagulation, acid separation, and struvite precipitation were innovatively set up to remove 98.1% of the ammonia nitrogen and 24.8%–52.3% of unavailable organics in the solution. The conditioned solution could be bio-converted to lipids at about 1.95 g/L with 39.7% lipid content, which was comparable to that achieved with waste activated sludge. The proportions of monounsaturated and polyunsaturated fatty acids were enhanced to 67.1%–74.4% by the integrated conditioning processes. Lipids produced from dewatered sludge were proposed to be favorable raw materials for biodiesel production.