Multi-step approach to add value to corncob: production of biomass-degrading enzymes, lignin and fermentable sugars

This work presents an integrated and multi-step approach for the recovery and/or application of the lignocellulosic fractions from corncob in the production of high value added compounds as xylo-oligosaccharides, enzymes, fermentable sugars, and lignin in terms of biorefinery concept. For that, liquid hot water followed by enzymatic hydrolysis were used. Liquid hot water was performed using different residence times (1050 minutes) and holding temperature (180200 °C), corresponding to severities (log(R0)) of 3.364.64. The most severe conditions showed higher xylo-oligosaccharides extraction (maximum of 93%) into the hydrolysates and higher recovery of cellulose on pretreated solids (maximum of 65%). Subsequently, hydrolysates and solids were used in the production of xylanases and cellulases, respectively, as well as, pretreated solids were also subjected to enzymatic hydrolysis for the recovery of lignin and fermentable sugars from cellulose. Maximum glucose yield (100%) was achieved for solids pretreated at log(R0) of 4.42 and 5% solid loading.Michele Michelin is a recipient of a FCT fellowship (SFRH/BPD/ 100786/2014). ThisstudywassupportedbythePortugueseFoundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-010145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. Héctor Ruiz would like to thank the financial support to the Mexican Science and Technology Council (CONACYT, Mexico) for the Basic Science Project-2015-01 (Ref. 254808) and the Energy Sustainability Fund 2014-05 (CONACYT-SENER), Mexican Centre for Innovation in Bioenergy (Cemie-Bio), and Cluster of Bioalcohols (Ref. 249564). We thank Dr. Nelson Lima from MUM (Micoteca da Universidade do Minho, PT) that gently provided the Trichoderma reesei fungi.