Production of hydrogen from lignocellulosic biomass using biological methods is an alluring approach to generate green and clean energy. However, the challenges levied by structural and compositional aspects of lignocellulosic biomass block the way to harness their complete energy potential. The review revisits the available methods of pretreatment to augment the accessibility of carbon source required for microorganism to perform biomass to hydrogen conversion. The fermentation methods that have been employed for years for bio-hydrogen production are discussed in brief to provide the background of biological routes of hydrogen production. The review further highlights the latest research trends and upgrades in technologies including the identified novel microbial strains, reactor configurations, integrated schemes of fermentations, nanocatalysts addition and the genetic engineering tactics to enhance the competence of hydrogen producing bacteria. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.