Biohydrogen (H2) is a clean, renewable energy source with zero carbon emissions, offering a sustainable alternative to fossil fuels. It holds promise for green energy production, fuel cells, and industrial applications, supporting the transition toward a hydrogen-based economy. Microbial cell exhibits one of the strong presence to produce increased amount of H2 either by natural selection, co-culture, using advance genetic engineering strategies. No potential microbial cell is yet to be introduced that can compete upon conventional fuels by natural selection. Alternatively, co-culture and genetic engineering are now opted to boost the H2 production whereas microbial compatibility and pathways are tested to achieve optimum level of H2. Co-culture systems represent an advancement over monoculture by utilizing two or more compatible microorganisms to enhance biohydrogen production through synergistic interactions. Genetic engineering interventions, such as gene cloning, mutagenesis, gene knockout, and CRISPR-Cas9, are employed to optimize metabolic pathways, improve substrate utilization, and increase hydrogen yields. This chapter explores different biohydrogen production pathways, emphasizing the role of metabolic engineering in enhancing microbial hydrogen (H2) yields. It seems in near future H2 can strongly replace the conventional fuels by using advance approaches. Ultimately, it can offers unique way to achieve sustainable environmental practises.