Integrated process to produce biohydrogen from wheat straw by enzymatic saccharification and dark fermentation

Abstract

In this study, different pretreatment methods, including lyophilization, hydrothermal pretreatment, and ultrasound combined with dilute alkali post-cooking, were investigated to enhance the efficiency of enzymatic saccharification and biohydrogen production of the wheat straw. All pretreatment methods could effectively remove lignin and hemicellulose while retaining cellulose, further enhancing the biomass accessibility for subsequently enzymatic saccharification and biohydrogen production. A reducing sugar concentration of 13.18 g/L was acquired when wheat straw was treated with ultrasound and dilute alkali cooking (RU). The sequential fermentative hydrogen yield of the substrate RU was 133.6 mL/g total solids (TS), which was 5.6-fold larger than that of the raw material (23.9 mL/g TS). The study confirmed that ultrasound combined with dilute alkali cooking was an effective method, which not only provided significant guideline for improving biohydrogen production but also presented helpful direction for the efficient pretreatment of other lignocellulosic biomass.