Browsing by Author "Keskin, T."

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Citation - Scopus: 3
Biohydrogen Production by Biological Water-Gas Shift Reaction and Bioelectrochemical Systems
(Elsevier, 2023) Keskin, T.; Gungormusler, M.; Bayar, B.; Abubackar, H.N.
Numerous strategies have been suggested to address the issue of global warming, which should be prioritized. Due to the availability of effective outcomes via well-established biotechnological applications, current developments have shown the benefits and superiority of nontraditional techniques for more sustainable bioprocessing. Several mesophilic and thermophilic bacteria have reported a distinct fermentation route using C1 gases (e.g. CO and CO2) frequently found in waste gas streams or syngas to generate bio commodities such as acetic acid, ethanol, butanol, 2,3-Butanediol, and hydrogen. This chapter discusses the aforementioned unconventional technologies, which include hydrogen generation technologies such as biological water-gas shift process and microbial electrolysis. Additional details on these technologies, including the effect of microbial community selection on metabolic pathways, the role of bioreactor design in enhancing liquid-gas mass transfer, process parameters, direct and mediated electron transfer mechanisms, and the characteristics of membranes that contribute to improved conductivity and stability under dynamic process conditions. Future prospects include the adaption of different process parameters and materials, such as biochar incorporation into fermentation, and the integration of technologies into bioelectrochemical systems in order to develop a more sustainable method of hydrogen generation. © 2023 Elsevier Ltd. All rights reserved.
Citation - WoS: 4
Citation - Scopus: 9
Optimizing Biohydrogen Production Yields by Employing Locally Isolated Thermophilic Bacteria From Hot Springs
(Elsevier Ltd, 2023) Akaçin, İ.; Ersoy, Ş.; Keskin, T.; Nalakath, Abubackar, H.; Güngörmüşler, Mine
A climate-neutral economy is anticipated to rely heavily on hydrogen because it enables emission-free transportation, heating, and manufacturing operations. Biohydrogen can be produced from various kinds of biological waste making the interest high. However, the yield and efficiency of the processes are still challenging. This study applied Box-Behnken statistical experimental design to investigate the influence of temperature (oC), pH, and CO volume (mL) together with the amount of Fe+2, Zn+2, and Ni+2 to enhance biohydrogen production yields from thermophilic cultures, both mixed and pure cultures isolated from hot springs in Izmir, Türkiye. The maximum H2 yields were reported as 0.13 mmolH2/mmolCO for mixed cultures, and the pure culture reached 2.5 fold higher yield (0.44 mmolH2/mmolCO). Bench-scale bioreactor with a custom-design micro sparger was successfully run for 7 days (highest 0.25 mmolH2/mmol CO). This is the first report in the literature with local isolates to demonstrate the optimization of H2 yields with a comparative approach, and scale-up in a 2 L bench scale bioreactor. The viability of using novel thermophilic isolates as biohydrogen producers was successfully proven. © 2023 Hydrogen Energy Publications LLC