The present paper reports the bio-refinery concept on exploiting the pre-treated non-detoxified corncob hydrolysate for bio-gas production and simultaneously utilizing the delignified cellulosic residue for bioethanol and black liquor for extraction of lignin. Based on the optimized conditions, corncob was pretreated with HNO3 at 121 degrees C for 15 min at a solid concentration of 20% (w/v). Maximum sugar concentration achieved was 110.12 mg mL(-1). The resultant corncob hydrolysate for bio-gas production was investigated in three anaerobic hybrid rectors. The reactors were operated at an OLR of 1.000, 1.428 and 2.500 g COD L-1 d(-1) and HRT of 10, 7 and 4 d. Maximum bio-gas production rate was in R 2 (18.7 Ld(-1)), followed by R-1 (18.41 Ld(-1)) and R-3 (12.06 Ld(-1)), respectively at 7 d HRT. The COD removal efficiency was 81.0, 83.3 and 79.0% in R-1, R-2 and R-3 reactors, respectively. Simultaneous saccharification and fermentation studies were carried out at three different enzyme loadings (9, 15 & 21 FPU g(-1) substrate) by Kluveromyces marxianus at 42 degrees C for 96 h. 1% NaOH pre-treated cellulosic residue yielded maximum ethanol concentration (33.14 mg mL(-1)) with 15 FPU g(-1) substrate enzyme load and at 87 h. The extracted lignin has a calorific value of 21.05 MJ kg(-1). (C) 2018 Elsevier Ltd. All rights reserved.