Cellulosic hydrogen production with a sequencing bacterial hydrolysis and dark fermentation strategy

Abstract

In this study, cellulose hydrolysis activity of two mixed bacterial consortia (NS and QS) was investigated. Combination of NS culture and BHM medium exhibited better hydrolytic activity under the optimal condition of 35 °C, initial pH 7.0, and 100 rpm agitation. The NS culture could hydrolyze carboxymethyl cellulose (CMC), rice husk, bagasse and filter paper, among which CMC gave the best hydrolysis performance. The CMC hydrolysis efficiency increased with increasing CMC concentration from 5 to 50 g/l. With a CMC concentration of 10 g/l, the total reducing sugar (RS) production and the RS producing rate reached 5531.0 mg/l and 92.9 mg/l/h, respectively. Furthermore, seven H 2-producing bacterial isolates (mainly Clostridium species) were used to convert the cellulose hydrolysate into H 2 energy. With an initial RS concentration of 0.8 g/l, the H 2 production and yield was approximately 23.8 ml/l and 1.21 mmol H 2/g RS (0.097 mmol H 2/g cellulose), respectively.