ABSTRACT
Most energy fuels, chemicals, and raw materials in our daily lives are derived from petroleum-based refineries. However, depleting fossil fuel reserves and increasing greenhouse gas emissions and severe pollution problems as the consequences of by-products from fossil fuel utilization are driving interests toward biorefineries for the production of energy and useful chemicals (Cherubini 2010; Menon and Rao 2012). In the energy and environmental sector, hydrogen (H2) has gained considerable interest owing to its higher specific energy content (122 MJ/kg), as well as water and energy being the sole oxidative reaction by-products (Balat and Kırtay 2010). At present, H2 production for industrial applications is mainly derived from thermocatalytic and gasification processes, which are highly dependent on fossil fuels. In comparison with the energy-intensive physicochemical routes for H2 production, biological processes can be operated at ambient conditions and are advantageous, as they can utilize renewable biomass (Das and Veziroglu 2001; Ghimire et al. 2015).
