Because of the benefits of increased hydrogen yields and greater substrate conversion efficiencies, systematic integration of dark and photo fermentation has gotten a lot of attention recently. This integration can be done in two stages sequentially or in a single stage, with the single-stage integration appearing to be more cost-effective. The primary operating techniques, key factors affecting hydrogen yields, and the overall increase in hydrogen yields realized in the single-stage integration biohydrogen processes are all thoroughly reviewed in this paper. Selection of a more complementary pair of dark and photofermentative microorganisms, optimization of common growing medium composition, and improved tactics for consistent growth pH management and lignocellulosic feedstock facilitation have been recognized as important issues that require more attention and development. Most investigations so far have been performed with batch digesters utilizing unpolluted culture and a sole wastewater, so, the method improvement of the combined two-steps procedure was yet in the early stages. The combination of dark-and photo-fermentation can be used to boost biohydrogen production and substrate utilization, making it the best option for commercial biohydrogen generation. The current status of single-stage integration biohydrogen technology has been reviewed, and its potential to become a reliable hydrogen production technology has been factually assessed, based on the insightful talks.

Anaerobic fermentation of organic waste has received widespread attention due to the enormous ecological and financial benefit it provides. It reduces wastes via reprocessing, saving capitals, lowering CFC gas emissions, and increasing financial flexibility in an indefinite future towards energy generation and garbage dumping. By minimizing landfill area, the influences of landfilling, and landfill preservation, the productive use of local garbage through recycling conserves resources. By lowering harmful emissions and pollutants, converting garbage as a sustainable energy resource can help the economic growth. As a result, the goal of this mini-review is to summaries critical criteria and provide useful data for an effective anaerobic process. It also discusses the advantages and disadvantages of various anaerobic processes for converting organic waste, as well as reactor technologies. Furthermore, this research emphasizes the difficulties and future prospects of the anaerobic system. Suitable heat, pH, inoculum to waste proportion, proper blending, and tiny particle size were all key components in an effective and efficient anaerobic process. As not all kinds of methods and digesters were successful to process the organic wastes, choosing the right anaerobic method and reactor is critical. This research is critical for continued work on waste-to-energy generation and gives crucial information on novel waste handling. Therefore, it can be suggested that the administration expand its funding for anaerobic process and support the vast untapped latent of bioenergy generation.