OPTIMIZATION OF BIOHYDROGEN PRODUCTION YIELDS WITH LOCALLY ISOLATED THERMOPHILIC BACTERIA FROM HOT SPRINGS

Abstract

Hydrogen, a carbon-free clean fuel and a strong alternative to conventional fossil energy sources, has many production strategies including biological routes, acknowledged as sustainable and environmentally friendly. The hydrogen yields acquired by those routes with either pure or mixed cultures are predominantly dependent on the environmental factors. Accordingly, in the literature, statistical experimental designs were proven to be useful to understand the effects of independent parameters including macro and micro nutrients, organic or inorganic substrates, pH and temperature. Within this scope, the aim of this study was to optimize the bio-H2 yields using the Box-Behnken design (BBD) with 3 different independent parameters (temperature(oC), pH and inorganic substrate (CO volume (mL)) with a comparative approach using both mixed and pure thermophilic cultures isolated from Izmir hot springs. The maximum H2 yields were reported as 0.13 mmol H2/mmol CO for mixed cultures at pH 7, 60oC and 15 mL CO addition whereas the pure culture reached 2.5 fold higher yields by 0.46 mmol H2/mmol CO. The results demonstrated the effectiveness of the utilization of the statistical design of experiments to improve the bioproduction yields via local thermophilic isolates. © 2022 Proceedings of WHEC 2022 - 23rd World Hydrogen Energy Conference: Bridging Continents by H2. All rights reserved.