The growing preoccupation for the e

The growing preoccupation for the environment and global
warming in conjunction with the adherence of signatory
countries to Kyoto Protocol including Algeria, all militate in
favour of using clean and renewable energy. Currently, several
technologies developed energy systems based on the use of
hydrogen as an optimal energy vector for the future.
Compared with steam reforming, thermochemical cracking or
gasification of coal, which are consuming fossil energy, electricity and heat, biological production of hydrogen operate
using only solar energy. However, biological production
occurs under ambient temperature and pressure conditions
do not require energy input. This production way is an
environment-friendly process and it permits the valorisation
of some natural resources, too often neglected.
The hydrogen gas photobiologically produced (i.e. biohydrogen) is considered as a secondary metabolite obtained by
microorganism metabolism released under particular conditions. According to microorganism species and biochemical
process, different biological ways of hydrogen production are
reported in the literature [1]. Biological hydrogen generation can
be classified into four categories: (i) direct biophotolysis using
green microalgae [2e4] and some cyanobacteria [5], (ii) indirect
biophotolysis with other cyanobacteria species and certain
nitrogen-fixing bacteria [6,7], (iii) photofermentation of waste
and effluents [8] and (iv) dark fermentation of rich sugar wastes
[9,10].