Comparative evaluation of the biohydrogen production potential of thermophilic microorganisms isolated from hot springs located in Izmir

Abstract

Biohydrogen production with the utilization of thermophilic microorganisms is a green process contributing to the mitigation of fossil fuel dependency. This study reports an improved water-gas shift reaction (WGSR) methodology with isolation of thermophilic and anaerobic microorganisms from 5 different closely-located hot springs, employing enrichment and characterization techniques to evaluate their biohydrogen production capacities with 100% CO in the headspace. Enriched mixed and pure cultures were screened for biohydrogen production. An isolate from Doğanbey hot spring reached the highest H2 yield of 0.43 mmol H2/mmol CO with a 43% CO conversion. Using growth profiling and morphologically with SEM imaging, this isolate was characterized biochemically, and was identified as an isolated bacilli shaped bacteria capable of producing hydrogen through WGSR. This is the first study to report potential thermophilic hydrogen producers in selected hot springs in the Izmir region.