Hydrogen and biodiesel production from food waste: a review

The rising food waste generation induces major issues of food security, pollution, and depletion of resources and arable land, thus calling for novel recycling practices such as converting food waste into fuels. Here we review the production of dihydrogen, thereafter named ‘hydrogen,’ and biodiesel from food waste, with focus on food waste composition and hydrolysis, hydrogen production and biodiesel production. Hydrogen production is done by dark fermentation and photofermentation. Biodiesel is produced by production of lipid-rich biomass using food waste and transesterification. We discuss lipids accumulation in oleaginous microorganisms and in black soldier fly larvae. Upscaling of hydrogen and biodiesel production is also presented. Optimal hydrogen yield ranges from 1 to 7 mol H2/mol hexose. After fermentation, the residual glucose should be less than 10% and volatile fatty acids should be less than 40%. Biomass lipids containing less than 1% polyunsaturated fatty acids is ideal for biodiesel production.