Isolation and characterization of photosynthetic bacteria from aquaculture wastewater for hydrogen production

Abstract

Hydrogen is a clean energy substitute to fossil fuels, also environmentally friendly and does not lead to global warming. Photosynthetic bacteria produce hydrogen from organic compounds by an anaerobic light-dependent electron transfer process. Two hydrogen-producing photosynthetic bacteria have been isolated from aquaculture wastewater enriched with succinate (electron donor) under facultative condition. The isolated bacteria were identified as Gram negative and rod shaped bacteria. During the photohydrogen production process, hydrogen gas is produced at 30ºC, initial pH of 7, and light intensity provided using white fluorescent lamp. The two isolated bacteria were then screened for hydrogen production using acetate and starch as substrate. Hydrogen production was measured using residual gas analyzer. These strains have the ability to utilize starch better than acetate as carbon sources for hydrogen production. The two strains, designated as AQ1 and AQ4, were identified to be Pseudomonas sp. via 16S rRNA characterization. The sequences have been deposited to GenBank with the accession number KJ854409 for Pseudomonas sp. AQ1 and KJ854410 for Pseudomonas sp. AQ4. In conclusion, the two isolates (AQ1 and AQ4) have been characterized as hydrogen producer in photohydrogen production process using starch and acetate as substrate. They have the potential to be used in simultaneous wastewater treatment and clean energy generation.