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Potential of Marine Biota and Bio-waste Materials as Feedstock for Biofuel Production
Published in Gunjan Mukherjee, Sunny Dhiman, Waste Management, 2023
Mostafa M. El-Sheekh, Hassan A.H. Ibrahim, Khouloud M. Barakat, Nayrah A. Shaltout, Waleed M.M. EL Sayed, Reda A.I. Abou-Shanab, Michael J. Sadowsky
Bio-hydrogen is a very promising solution to energy scarcity as it is renewable and could replace fossil fuels in the future (Chong et al. 2009). Presently, hydrogen is mostly produced via chemical means. It has been investigated that 99% of all living organisms utilize dihydrogen (H2). The majority of them are microbes that required a hydrogenase metalloenzyme to use H2 as a metabolite (Chong et al. 2009). Hydrogenases have been subdivided into three groups based on the active site metal: either FeFe-, NiFe-, or Fe-hydrogenase (Lubitz et al. 2014). Demirbas (2010) stated that a variety of bacteria fermented carbohydrates could result in the production of hydrogen and carbon dioxide. Also, cyanobacteria and some microalgae can produce H2, a potential biofuel product, through the following reaction (Melis 2002): 2H2O+light energy→O2+4H++4e−→O2+2H2
Algae-Mediated Bioelectrochemical System: The Future of Algae in the Electrochemical Operations
Published in Kuppam Chandrasekhar, Satya Eswari Jujjavarapu, Bio-Electrochemical Systems, 2022
Rehab H. Mahmoud, Hany Abd El-Raheem, Rabeay Y.A. Hassan
Hydrogen production from an algal biomass can be done in a variety of ways, including photobiological and fermentative methods (Shaishav et al., 2013). Chlamydomonas reinhardtii and Scenedesmus obliquus are the most studied microalgae to produce biohydrogen (Zhiman et al., 2011). The major enzyme that catalyzes these reactions is hydrogenase. In a photobiological reaction, ferredoxin is oxidized by the hydrogenase enzyme in the electron transfer chain, releasing hydrogen. In dark fermentation, hydrolysis and acidogenesis are carried out by hydrogen-producing bacteria such as Clostridium sp., Enterobacter sp., Lactobacillus sp., Bacillus sp., Klebsiella sp., and Citrobacter sp. (Kawagoshi et al., 2005; Rossi et al., 2012). Genetic alterations are being used to modify hydrogen generation pathways in algae in order to boost biohydrogen yield (Batyrova & Hallenbeck, 2017; Saifuddin & Priatharsini, 2016).
Hydrogen Production from Biomass
Published in Vladimir Strezov, Hossain M. Anawar, Renewable Energy Systems from Biomass, 2018
The organisms absorb solar energy and produce protons and electrons, and then electrons take part in the formation of ferredoxin (Saxena et al. 2009). The protons and electrons subsequently combine with each other and generate molecular hydrogen by the hydrogen-generating enzyme hydrogenase (Allakhverdiev et al. 2010). The organisms with this function may include green algae, cyanobacteria, green bacteria, purple bacteria, and others.
Crystal structure and electrocatalytic investigation of diiron azadiphosphine complex [Fe2(μ-pdt)(CO)4{(μ-Ph2P)2NH}] related to [FeFe]-hydrogenases
Published in Inorganic and Nano-Metal Chemistry, 2020
Jian-Rong Li, Yan-Hong Wang, Pei-Hua Zhao
Hydrogenases are a kind of the highly efficient enzymes that can catalyze both the reduction of proton and the oxidation of hydrogen in a variety of microorganisms. Among these enzymes, [FeFe]-hydrogenases (abbreviated to [FeFe]-H2ases) have been proven to catalyze the proton reduction to molecular hydrogen (H2) more efficiently than other types of hydrogenases.[1–3] Further crystallographic and spectroscopic investigations have shown that the active site of [FeFe]-H2ases comprises a butterfly [Fe2S2] cluster (namely, diiron subsite) with one of the Fe atoms linked to a cubic [Fe4S4] subcluster through the S atom of a cysteinyl ligand (Figure 1a),[4,5] in which there are several diatomic ligands such as CO, CN- and one dithiolate bridge coordinated to two iron centers.[6] Especially, the bridging dithiolate cofactor has been definitively determined to be an azadithiolate (adtNH, SCH2NHCH2S) in this enzyme (Figure 1a),[7–9] where the pendant amine in the adt bridge plays an important impact on the extremely fast formation of H2 in the natural system.[7,8]
Progress in microbiology for fermentative hydrogen production from organic wastes
Published in Critical Reviews in Environmental Science and Technology, 2019
Nature has evolved plenty of hydrogenases. Figure 2 shows the classification of hydrogenases. The hydrogenases are categorized into [Fe]-, [FeFe]- and [NiFe]-hydrogenases according to the metal content of the active site. Some of these hydrogenases are oxygen-sensitive, like [Fe]–hydrogenases and [FeFe]–Hydrogenases, they can be irreversibly inactivated when exposed to oxygen; some of them are oxygen-resistant, like [NiFe]–hydrogenases, they can be suppressed by oxygen but when the oxygen is eliminated, their activity can be recovered; others are oxygen-tolerant, they are aerobically active and catalyze hydrogen oxidation, these hydrogenases are rare. Some hydrogenases catalyze the reversible hydrogen oxidation and hydrogen formation, while others are only active in either hydrogen formation or hydrogen consumption. Microorganisms usually own several hydrogenases, and each of them functions in different ways.
Enhanced biohydrogen production from leather fleshing waste co-digested with tannery treatment plant sludge using anaerobic hydrogenic batch reactor
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2018
Salma Aathika A. R, D. Kubendran, M. Yuvarani, D. Thiruselvi, T. Amudha, P. Karthik, S. Sivanesan
A delayed start-up of fermentation process was observed as the hydrogen evolution began to occur after 5 days of incubation of the seed. This clearly shows that the system underwent hydrolysis and acidogenesis at the beginning, and then, the microorganisms started evolving hydrogen from the 5th day after entering the acetogenic phase in the metabolic pathway. Slowly, the hydrogen rates decreased, in spite of restricting the methanogens, thereby showing a depletion in the performance of the system. From Figure 1 (b), it is observed that the system remained dormant between the 9th and the 19th day, due to the declination in the microbial population. Bio-hydrogen production has a very short digestion time when compared to bio-methane production, but as the primary focus lies on running commercial units both economically and sustainably, the system was enriched again to attain an exponential growth of bacteria for enhancing the gas production. Nutrients were added to the serum bottles at 0.5 mL each on the 16th day, which led to a significant increase in the trend from the 21st day. The gas was measured up to 34 days until the bio-hydrogen stopped. It was observed that, though the production of bio-hydrogen was possible after addition of nutrients to the system, the daily gas production rate was not as high as it remained during the first cycle. Also, the initial pH affects the lag phase immensely, as the results obtained by Fan et al. support the result obtained by depicting that the lag time was 74, 41, 19–28 hours for the pH of 5, 6 and 7–10 respectively. Nevertheless, the pH stimulates the micro-organisms in achieving the maximum hydrogen yield as the activity of hydrogenase gets inhibited at both low and high pH during the fermentation process (Fan, Kan, and Lay 2006).