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The increasing levels of carbon dioxide (CO2) in the atmosphere, primarily due to the use of fossil fuels, pose a significant threat to the environment and necessitate urgent action to mitigate climate change. Carbon capture and utilization technologies that can convert CO2 into economically valuable compounds have gained attention as potential solutions. Among these technologies, biocatalytic CO2 hydrogenation using bacterial whole cells shows promise for the efficient conversion of CO2 into formate, a valuable chemical compound. Although it was discovered nearly a century ago, comprehensive reviews focusing on the utilization of whole‐cell bacteria as the biocatalyst in this area remain relatively limited. Therefore, this review provides an analysis of the progress, strategies, and key findings in this field. It covers the use of living cells, resting cells, or genetically modified bacteria as biocatalysts to convert CO2 into formate, either naturally or with the integration of electrochemical and protochemical techniques as sources of protons and electrons. By consolidating the current knowledge in this field, this review article aims to serve as a valuable resource for researchers and practitioners interested in understanding the recent progress, challenges, and potential applications of bacterial whole cell catalyzed CO2 hydrogenation into formate. [ABSTRACT FROM AUTHOR]

We present an Ir complex that extracts electrons from H2 at room temperature and stores them as a H2-derived energy carrier (H2EC) at room temperature. Furthermore, we demonstrate that this complex reduces CO2 to a metal–CO22− species at room temperature, and present the first electrospray ionisation mass spectrum for this compound. [ABSTRACT FROM AUTHOR]

Membrane-bound respiratory [NiFe]-hydrogenase (MBH), a [H.sub.2]-uptake enzyme found in the periplasmic space of bacteria, catalyses the oxidation of dihydrogen: [H.sub.2] → 2[H.sup.+] [2e.sup.-] (ref. 1). In contrast to the well-studied [O.sub.2]-sensitive [NiFe]-hydrogenases (referred to as the standard enzymes), MBH has an [O.sub.2]-tolerant [H.sub.2] oxidation activity (2-4); however, the mechanism of [O.sub.2] tolerance is unclear (5). Here we report the crystal structures of Hydrogenovibrio marinus MBH in three different redox conditions at resolutions between 1.18 and 1.32 Å. We find that the proximal iron-sulphur (Fe-S) cluster of MBH has a [4Fe-3S] structure coordinated by six cysteine residues-in contrast to the [4Fe-4S] cubane structure coordinated by four cysteine residues found in the proximal Fe-S cluster of the standard enzymes-and that an amide nitrogen of the polypeptide backbone is deprotonated and additionally coordinates the cluster when chemically oxidized, thus stabilizing the superoxidized state of the cluster. The structure of MBH is very similar to that of the [O.sub.2]-sensitive standard enzymes except for the proximal Fe-S cluster. Our results give a reasonable explanation why the [O.sub.2] tolerance of MBH is attributable to the unique proximal Fe-S cluster; we propose that the cluster is not only a component of the electron transfer for the catalytic cycle, but that it also donates two electrons and one proton crucial for the appropriate reduction of [O.sub.2] in preventing the formation of an unready, inactive state of the enzyme., An increasing interest in exploring [H.sub.2] as a clean energy carrier has encouraged the use of hydrogenases as efficient catalysts for [H.sub.2] oxidation in fuel cells and for [H.sub.2] production. [...]

J-resistance properties of automatic narrow gap gas tungsten arc welds (NGGTAWs) for ferritic primary loop piping were investigated. The piping diameter is 1066 mm, and its thickness is 76 mm. The tensile, microhardness, and J-R tests were performed, and microstructures of the welds were examined. Tensile and J-R tests were conducted at 316[degrees]C and 177[degrees]C for temperature effect, and at 1 mm/min and 1000 mm/min for strain rate effect. The results were compared with other welds, which are fabricated by the conventional shielded metal arc weld (SMAW) process. The NGGTAW welds investigated in this paper have lower J-R curves than the SMAW welds. Fracture surfaces of the NGGTAW welds showed deep ditches and holes due to inclusions and pores. It is believed that the high density of the inclusions and the pores, which exist in the NGGTAW welds, is responsible for this lower toughness and the fracture surface appearances. Therefore, to improve the NGGTAW weld toughness, it is recommended that sulfur content should be limited to a considerably low level, and the pores should be eliminated by modifying the welding procedure specification. [DOI: 10.1115/1.2967810] Keywords: narrow gap welding, J-integral, LBB, inclusion, pore

The thermophilic, aerobic, obligately autotrophic, hydrogen-oxidizing bacterium, Hydrogenobacter thermophilus TK-6, synthesizes 2-oxoglutarate:ferrodoxin oxidoreductase, a key enzyme in the reductive tricarboxylic acid cycle. Sequence analysis shows it has a molecular mass of about 105 kilodaltons. Enzymatic analysis shows it is thermostable, has an optimum pH from 7.6-7.8 and undergoes oxidation at temperatures above 80 degrees Celsius.

This paper reports the first example of C−H arylation of benzene under mild conditions, using H2 as an electron source {turnover numbers (TONs)=0.7–2.0 for 24 h}. The reaction depends on a Rh‐based electron storage catalyst, and proceeds at room temperature and in aqueous solution. Furthermore, the H2 is inactive during the radical transfer step, greatly reducing unwanted side reactions. [ABSTRACT FROM AUTHOR]