Sustainable biorefinery concept for biofuel production through holistic volarization of food waste

The aim of this study was to utilize the whole food waste in two stages. In the first stage, the carbohydrate and protein fractions of food waste recovered after enzymatic hydrolysis was used to cultivate heterotrophic microalgae, resulting in biomass yield of 0.346 +/- 0.09 g/g(sugars) and lipid yield of 0.216 +/- 0.06 g/g(sugars). In the second stage, oil (14.15% w/w) was extracted from food waste after hydrolysis and converted to biodiesel by a two-step transesterification reaction that generated 135.8 g/kg(food waste) of fatty acid methyl esters and 13.8 g/kg(food) (waste) of crude glycerol. Finally, crude glycerol obtained from both processes was used at 20 g/L to cultivate heterotrophic microalgae, resulting in a cell dry weight and total lipid concentration of 6.23 g/L and 2.91 g/L, respectively. A total 248.21 g of fatty acid methyl esters were obtained from the 1 kg of food waste through this integrated process.