Table Open ponds and raceways Photobioreactors Fig
Inhibitors can also be employed to increase H2 generation but considered inferior to the above process . Some Omecamtiv mecarbil of Platymonas and Chlamydomonas are insensitive against above described sulfur deprivation where inhibitors and nitrogen deficiency can bring out enhanced hydrogen production . Photoproduction of seaweed Platymonas helgolandica has also been investigated for hydrogen producing potential. This method of biological production of hydrogen is environmentally safe, efficient enough and non-hazardous . Co-cultivation of algae with bacteria can effective intensive hydrogen production  but the system will be difficult to understand as prions involves complex biological reaction. Though cultivation under stressed condition gives good results, genetic engineering application in biohydrogen production will be a novel attempt and expected to bring notable fortunes .
5. Algal biofuels and characteristics
Currently, algal biofuels are non-viable due to cost factors, but expected to be practically viable in the near future. Various fuel products are obtained from algae of which methane, ethanol, butanol and biodiesel are most significant. Other fuel products include bio-oil, hydrogen and other hydrocarbon derivatives (Fig. 5).