Outlook of biohydrogen production from lignocellulosic feedstock using dark fermentation – a review

Hydrogen becomes a promising alternative energy carrier to fossil fuels since it is clean, renewable, contains high energy content and does not contribute to greenhouse effect. Therefore, using cheap or renewable resources, such as lignocellulosic materials, as the feedstock for hydrogen production, in particular, dark fermentative hydrogen production has a great potential to give major contribution to future energy supply. The main challenges are the low hydrogen yield arising from poor efficiency on direct microbial assimilation of cellulosic materials. Considerable research efforts have been made to improve the pretreatment and hydrolysis of lignocellulosic materials. Development of novel and effective cellulase enzymes, optimization and improvement of cellulase system, as well as engineering approaches on cellulose pretreatment and saccharification are gaining increasing interest. Information from genomics and molecular genetics combined with improved genetic engineering offer a wide range of possibilities for enhancing performance of cellulose feedstock utilization and biohydrogen production. This study reviews key technologies and variables to be considered during biohydrogen production from lignocellulosic feedstock.