BIOREFINING OF QUINOA RESIDUES FOR PRODUCTION OF ADVANCED BIOFUELS AND BIOPOLYMERS

Using local residues as raw materials for biorefineries is important for sustainable development. Quinoa stalks can be considered raw materials of choice for local biorefinery initiatives in Bolivia. This investigation aims at proposing a biorefinery process to be applied to quinoa residues using our know-how on lignocellulose bioconversion and the asset of robust microbes isolated from extreme environments. The proposed process consists in treating quinoa stalks in a sequence including extraction of saponins, acid hydrolysis of hemicelluloses and enzymatic saccharification of cellulose for producing hydrolysates to be used in bioconversion processes with different alternative microbes. Saponins are extracted with aqueous ethanol, the saponins-free material is subjected to sulfuricacid-catalyzed hydrothermal pretreatment for separating a stream of hemicellulosic sugars and a cellulignin stream that is then saccharified with commercial cellulases. The extracted saponins can further be processed to value-added products or can be used in the enzymatic saccharification stage for enhancing cellulose conversion. The produced hydrolysates are suitable substrates for producing bacterial biopolymers or ethanol. Residual lignin from the enzymatic saccharification can be upgraded for value-added applications. The results of this investigation show the potential of biorefining of quinoa residues for producing biopolymers using halotolerant bacteria isolated in Bolivian Altiplano.