Biohydrogen production using psychrophilic bacteria isolated from Antarctica

• By first time, it is reported the biohydrogen production by microorganism isolated from Antarctic samples.
• Psychrophilic microorganisms are natural biohydrogen producers.
• GA051 clone closely related to Janthinobacterium agaricidamnosum (Y08845) has the maximum biohydrogen production rate.
• GA024 strain closely related to Polaromonas jejuensis strain JS12-13 (NR044379) has the maximum biohydrogen yield.

The growing interest in hydrogen as a fuel has intensified the search of novel approaches for new production processes, among which biohydrogen stands out. Currently mesophilic and thermophilic microorganisms have been used as inocula, and practically no information on the use of psychrophilic microorganisms is available. In this study, the capability of producing biohydrogen by 14 cultivable psychrophilic bacteria, which were isolated from samples of Antarctica, was evaluated. Microorganisms were typified using molecular techniques, and biohydrogen production screening was performed in 120 ml serological bottles with a production medium containing 2.75 g/l tryptone, 0.25 g/l yeast extract, and 20 g/l glucose as carbon source. Results showed that all psychrophilic strains produced biohydrogen from 34.8 to 253.3 ml. Maximum production and production rate of 253.3 ml and 16.64 ml/l/h, respectively were attained by GA051, which is closely related to Janthinobacterium agaricidamnosum (Y08845) with an identity of 98%, whereas the maximum biohydrogen yield of 1.57 mol H2/mol glucose was for the GA024 strain, closely related to Polaromonas jejuensis strain JS12-13 (NR044379) with an identity of 99%. Metabolites were also tested and the main byproducts were organic acids and ethanol. Our results demonstrate that psychrophilic bacteria isolated from Antarctica have a high potential to be used for developing new biotechnological processes for biohydrogen production.