Plastic bags as simple photobioreactors for cyanobacterial hydrogen production outdoors in Moscow region

Abstract

The application of transparent plastic bags with a gas barrier layer as inexpensive photobioreactors for H2 production by the cyanobacterium Anabaena sp. PCC 7120 ∆Hup mutant cells was explored outdoors in Moscow region for the first time. Two experiments were performed in July and August, the average daily temperature being 21.7 and 20.6 °C, the average daily light intensity being 290 and 340 µmol photon m−2 s−1 in experiment #1 and #2, respectively. The maximal H2 production rate was 20.6 mL day−1 L−1 of culture, with accumulation of 33.2 mL L−1 during 5 days and a final H2 content of 1.1% (v/v). Molecular nitrogen added to the Ar gas at 3.3% significantly affected neither the rate nor the duration of H2 production. Low morning temperatures as well as high daytime light intensities (especially at low cell concentrations) seemed to reduce the H2 production rate. The activities obtained were lower as compared to the previously reported data. It could be attributable to suboptimal weather conditions and simple device arrangement. However, results prove that H2 production by cyanobacteria is still feasible outdoors in plastic bags, the cheapest photobioreactors.