Potential of Lignocellulic Waste as Substrate for Microalgal Cultivation

Abstract

The As the human population is rising, and with it the need for novel food protein sources and a reduction of greenhouse gas emissions is increasing in importance. An approach to tackle both those concerns would be microalgal cultivation. Microalgae can be cultivated on non-arable land and generally needrequire less space than the production of currently established protein sources, such as meat and soy. However, the cultivation of microalgae in a sustainable and economically viable manner is still in the developing phase. Moreover and C. vulgaris produced proteins includeing all essential amino acids needed for a balanced human and animal nutrition. To reduce production costs and increase biomass yields, hydrolysates from abundantly available lignocellulosic waste streams, could be used as substrates such as wheat straw, potato peels and apple cores could be used as substrates for heterotrophic and mixotrophic cultivations of Chlorella vulgaris. By hydrolyzing C5 and C6 sugars contained in those lignocellulosic substrates through liquid hot water hydrolyzation, furfural and 5-Hydroxymethylfurfural (HMF) get synthesized in the process, which are known inhibitors to other microorganisms. In this presentation, I discuss the impact of furfural and HMF on the mixotrophic and heterotrophic cultivation of Chlorella vulgaris. By investigating the impact of these inhibitors, the metabolism of furfural and HMF to two unknown products was observed. By LC-IM-QTOFMS analysis coupled with an UV/VIS detector, we identified the two metabolites as furoic acid stemming from furfural and 2-methylfuran from 5-hydroxymethylfurfural respectively.