BIOHYDROGEN PRODUCTION

BIOHYDROGEN PRODUCTION

 Hydrogen gas is an important alternative fuel that is sustainable and environment friendly. Because with combustion only water and energy is formed.

 The fuel with the highest energy density among the fuels (143 kJ / g)

 Hydrogen is produced by physical, chemical

and biological methods.

Today, 96% of hydrogen is produced from fossil fuel sources 48% natural gas,

30% from oil 18% from coal,

4% from water electrolysis

Although hydrogen production by biological way constitutes

a small portion, it is thought that this will increase with the

developed techniques.

 Hydrogen can be carried anywhere easily and safely

 can be used in industry, homes and vehicles

 inexhaustible,

 clean,

 easily converting to heat, electrical and mechanical energy,

 carbon-free,

 is an economic and light source of energy.

Fuel properties of hydrogen



Biological production of hydrogen occurs through two main mechanisms:



Photobiological production: photosynthetic

microorganisms such as algae or photosynthetic bacteria are used in this process.



Fermentation: Facultative anaerobes and obligate

anaerobes, hydrogen-producing microorganisms,

are used in this process.

 There are several technologies used for the production of biohydrogen. These are;

 Direct biophotolysis

 Indirect biophotolysis

 Photo-fermentation

 Hydrogen synthesis by water-gas shift reaction

 Anaerobic digestion

 Clostridium pasteuranium, C.butrycum, C.beijerinkii are high hydrogen producers; C. propionicum is a weak

hydrogen producer.

Important enzymes

 Biological hydrogen production reactions depend on

hydrogenase or nitrogenase enzymes that catalyze the

reduction of protons.