Food Waste Valorization by Microalgae

In early twenty-first century, both developed and developing countries aim to avoid burning of fossil fuel in an effort to reduce the greenhouse gas emissions and impacts on global warming. Microalgae are potential key players for tackling greenhouse gas emissions and for providing feedstock for renewable energy production. Microalgae utilize freely available solar radiation as an energy source to extract protons and electrons from water to ultimately convert atmospheric carbon dioxide into organic carbon manifested in the growth rates and biomass concentrations. The microalgal biomass consists of biopolymers (protein and carbohydrate), lipid and pigments, which provides a platform for producing value-added products or for utilization as renewable energy resources. However, carbon and nutrient requirements for their cultivation are major bottlenecks adding to the overall production costs. Alternatively, food waste could be used for cultivation of microalgae after suitable pretreatment to solubilize organic carbon polymers. In an integrated bio-refinery approach, harvested microalgal biomass, value-added products are extracted sequentially, with the leftover components (those that do not have a significant market value) to be used in energy generation through anaerobic digestion/fermentation processes. This chapter will provide an overview on food waste valorisation by and most suitable species of microalgae, a brief discussion on adopting various pretreatment techniques for solubilization of carbon from food waste for easy valorisation by microalgae.