Zahra Shamsizadeh - Environmental Science and Technology Research Center, Department of Environmental Health Engineering, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Mohammad Mehralian - Department of Environmental Health Engineering, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Maryam Khashij - Environmental Science and Technology Research Center, Department of Environmental Health Engineering, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.

Whereas quantity of fossil fuels is limited, Large scale production of hydrogen is a necessity for the world. It is concluded that hydrogen is the most promising option in the succession of fuel evolution. Combustion of hydrogen results lower NOx emissions (more than 57-73%) from internal combustion engines, which is environmentally more desirable 1. It does not produce greenhouse gases; instead it has a high energy yield (142 kj/g) which is 2.75 times more than that of any fuel. Compared with alternative technology, namely hydrogen production from fossil fuels, biomass and water using chemical, biological process generate large quantities of hydrogen; however, the operation is to some extent difficult. Among biological H2 production processes such as (photosynthetic hydrogen production and fermentative hydrogen production), the fermentative production has been considered as a viable and effective method. In general, it has some significant advantages compared to photosynthetic hydrogen production and produces hydrogen continuously without light using various kinds of substrates, low cost and finally biogas (H2) production. Therefore, fermentative hydrogen production has been received increasing attention in recent years 2- 5.

Essential Requirement,Bio-Hydrogen Production,Anaerobic Condition