Valorization of sugarcane bagasse and sugar beet molasses using Kluyveromyces marxianus for producing value-added aroma compounds via solid-state fermentation

The growing demand for natural products has favored the development of bioprocesses for obtaining value-added products in the fragrance and flavor sector. Solid-state fermentation (SSF) of agro-industrial residues together with generally recognized as safe (GRAS) strains like Kluyveromyces marxianus appears as a remarkable alternative for producing aroma compounds. In this study, a continuous air supplied system was used for optimizing the production of fruit like compounds via SSF of a mixture of sugarcane bagasse/sugar beet molasses employing K. marxianus. The main operational parameters were evaluated to identify the best conditions for their biosynthesis. Maximum cumulative volatile production was achieved at 40 degrees C, 35% molasses (dry basis) and specific air flow rate (S-AFR) 0.14 L h(-1)g(ITS)(-1) reaching 161 mg(TVOL) per gram of initial total solids content (ITS). The main components of the produced volatiles were alcohols (43%) while ester species constituted only 18%. Selectivity to ester species was enhanced working at 30 degrees C, 25% molasses and S-AFR 0.11 L h(-1)g(-1) (ITS), maximizing the ester content to 47.6 mg(Ester) g(ITS)(-1). In this case, a pleasant fruity odor was perceived thanks to the higher ester content (35%). Stressing conditions for K. marxianus like high temperatures and limiting nitrogen availability seem to be key factors for promoting the production of the volatile compounds. (C) 2017 Elsevier Ltd. All rights reserved.