Enhanced hydrogen photoproduction by non-heterocystous cyanobacterium Plectonema boryanum

Abstract

Nitrogenase activity was derepressed in Plectonema boryanum following 18-24 h of microaerobic incubation. The cyanobacterium evolved hydrogen at a slow rate. Addition of reducing substances (sulfide, sulfite or dithionite) to the diazotrophic cultures resulted in an increase in nitrogenase activity or photoproduction of hydrogen. The reducing substances also restored phycocyanin degradation.