Lee D.-JDUU-JONG LEE2022-03-222022-03-22202109608524https://www.scopus.com/inward/record.uri?eid=2-s2.0-85115994965&doi=10.1016%2fj.biortech.2021.126021&partnerID=40&md5=e1e46f0924f6f6ccf2871402e68ba517https://scholars.lib.ntu.edu.tw/handle/123456789/598191Microbial fermentation of organic matter under anaerobic conditions is currently the prominent pathway for biohydrogen production. Organic matter present in waste residues is regarded as an economic feedstock for biohydrogen production by dark and photo fermentative bacteria. Agricultural residues, fruit wastes, vegetable wastes, industrial wastewaters, and other livestock residues are some of the organic wastes most commonly used for biohydrogen production due to their higher organic content and biodegradability. Appropriate pretreatments are required to enhance the performance of biohydrogen from complex organic wastes. Biohydrogen production could also be enhanced by optimizing operation conditions and the addition of essential nutrients and nanoparticles. This review describes the pathways of biohydrogen production, discusses the effect of organic waste sources used and microbes involved on biohydrogen production, along with addressing the key parameters, advantages, and difficulties in each biohydrogen production pathway. ? 2021 Elsevier LtdBiohydrogenDark fermentationNanotechnologyOrganic wastesPhoto fermentationAgricultural wastesAgricultureBiodegradabilityBiogeochemistryFeedstocksFermentationHydrogen productionOrganic compoundsBio-hydrogenBio-hydrogen productionEnergy sourceEnvironment friendlyFuture prospectsMicrobial fermentationProduction pathwaysBacteriahydrogennanoparticleorganic matteranoxic conditionsbacteriumbiogascrop residuefermentationmicrobial activityagricultural wastebiodegradabilityenergy resourcefruit wasteindustrial wastelivestockmicroorganismnanotechnologynonhumannutrientorganic wastephotosynthesisReviewvegetable wastewastewaterHydrogenWaste Water[SDGs]SDG6[SDGs]SDG7[SDGs]SDG12review10.1016/j.biortech.2021.126021346003152-s2.0-85115994965