Biodiesel production using microbial lipids derived from food waste discarded by catering services.

Biodiesel production using microbial oil derived from food waste discarded by the hospilatity sector could provide a sustainable replacement for diesel fuel. Discarded potato peels were used in solid-state fermentations of Aspergillus awamori for the production of glucoamylase (30 U/g) and protease (50 U/g). Hospitality food waste hydrolysis led to 98% (w/w) starch to glucose conversion yields. Crude hydrolyzates were used in shake flask fermentations with the oleaginous yeast Rhodosporidium toruloides Y-27012 leading to 32.9 g/L total dry weight (TDW) with 36.4% (w/w) intracellular lipid content. Fed-bath bioreactor cultures resulted in TDW of 53.9 g/L and lipid concentration of 26.7 g/L. Principal component analysis showed a fatty acid profile similar to soybean oil and solid food waste oil. Microbial oil was transesterified into biodiesel with satisfactory performance considering the European standard EN 14214. This work demonstrated that valorization of food waste for biodiesel production is feasible.