Hydrolysis of corn cob by extremely low concentration maleic acid

In order to investigate the hydrolysis characteristics of corn cob, two-step hydrolysis method of hot liquid water (HLW, to hydrolyze most of the hemicellulose and expose the cellulose) and extremely low concentration maleic acid (ELMA, to hydrolyze the cellulose to oligosaccharide and glucose) was approached. DNS and HPLC analyses indicated that there was 12.24 g/L reducing sugar in the hydrolysate of HLW (200℃, 10 min, 4 MPa, 500 r/min, liquid-solid ratio 20:1 mL/g), and 91.76% hemicellulose was dissolved in the water, with 3.61% cellulose loss; There was 9.94 g/L reducing sugar in the hydrolysate of ELMA (0.1%, 220℃, 20 min, 4 MPa, 500 r/min, liquid-solid ratio 20:1 mL/g), and 95.17% cellulose was dissolved, but only about one-third converted to reducing sugar. By means of GC-MS, a large number of hydrolysis products of lignin were found in step two, such as phenol and benzoic acid compounds with active groups which can react with the sugar degradation products, to speed up the degradation of glucose. Some factors affecting the extremely low concentration maleic acid hydrolysis were studied, which can instruct rational better use of maleic acid hydrolysis. The hydrolysis performance of maleic acid can be promoted by improving the reactors to make degenerations of sugar and lignin discharged timely, which can provide a guidance for the application of maleic acid in biomass hydrolysis.