Production of biohydrogen by rhodobacter sphaeroides in pulp and paper mill effluent through photofermentation

Worldwide industrial development during the past century has led to the depletion of fossil fuel as global energy requirements are mostly dependent on fossil. These concerns have drawn significant attention and effort around the globe to develop renewable biofuel to replace the existing non-renewable fossil fuel. In relation to this matter, photofermentative biohydrogen production provides opportunities for sustainable energy (biohydrogen) from reutilizing industrial effluent via photosynthetic microorganisms. Technologies in producing biohydrogen from industrial effluent through photofermentation are well developed. However, there have been limited studies of applying ultrasonication as a pretreatment method on wastewater and the cells prior to photofermentative biohydrogen production process. Ultrasonication on lignocellulosic type of wastewater as a pretreatment could remove or weaken the structure of lignin and increase the surface area of the material, which helps the photosynthetic bacteria to digest the substrate more effectively. Ultrasonication on cells could modify the bacterial membrane structure, improve cell activities and the release of intracellular enzymes. The enzymes help to degrade large molecules into smaller molecules which facilitate the diffusion of molecules into the cell. The ultrasonication pretreatment effect on photofermentative biohydrogen production using pulp and paper mill effluent (PPME) as a substrate remains unknown. Thus, the main aim of this project was to investigate the feasibility of reutilizing PPME as a substrate for photofermentative biohydrogen production. In the present study, ultrasonication method was also applied as a pretreatment process for both PPME and Rhodobacter sphaeroides NCIMB8253 prior to biohydrogen production process.