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Baeyer-Villiger (BV) oxidation of cyclohexanone to epsilon-caprolactone in a microbial system expressing cyclohexanone monooxygenase (CHMO) can be influenced by not only the efficient regeneration of NADPH but also a sufficient supply of oxygen. In this study, the bacterial hemoglobin gene from Vitreoscilla stercoraria (vhb) was introduced into the recombinant Escherichia coli expressing CHMO to investigate the effects of an oxygen-carrying protein on microbial BV oxidation of cyclohexanone. Coexpression of Vhb allowed the recombinant E. coli strain to produce a maximum epsilon-caprolactone concentration of 15.7 g/l in a fed-batch BV oxidation of cyclohexanone, which corresponded to a 43% improvement compared with the control strain expressing CHMO only under the same conditions.
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http://dx.doi.org/10.4014/jmb.1409.09060 | DOI Listing |
Chem Sci
August 2025
Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, State Key Laboratory of Synergistic Chem-Bio Synthesis, Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University Shanghai 200240 China
Adipic acid is an essential platform molecule for polymer production and is industrially manufactured by thermochemical oxidation of the cyclohexanone/cyclohexanol mixture (KA oil). Alternatively, electrifying provides a green and sustainable route to synthesizing adipic acid, but has been restricted by the low catalytic efficiency. Herein, we report that a nickel hydroxide electrocatalyst functionalized with 4,4'-bipyridine (Bipy-Ni(OH)) delivers a 3-fold greater productivity compared with that of pristine Ni(OH), achieving an excellent yield (90%) towards efficient adipic acid electrosynthesis.
View Article and Find Full Text PDFChem Commun (Camb)
August 2025
State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Department of Pharmacy, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
This study introduces an Fe/anthraquinone dual catalytic system for oxidative cleavage of non-strained cyclohexanones to mono-carboxylic acids under mild visible-light conditions (0 °C). Efficient activation of inert C-C bonds oxygen-centered radical-mediated cleavage is achieved, providing a sustainable approach to valorize bulk chemicals and synthesize pharmaceutical intermediates.
View Article and Find Full Text PDFJ Org Chem
August 2025
Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, Hunan Province Key Laboratory of Green Organic Synthesis and Application, College of Chemistry, Xiangtan University, Xiangtan 411105, China.
A novel Brønsted acid-catalyzed oxa-Pictet-Spengler reaction was developed for the efficient synthesis of indole-fused pyran derivatives under metal-free conditions. The proposed mechanism involves acid-mediated protonation of cyclohexanone to generate an electrophilic intermediate that undergoes attack by an oxidized indole species. Subsequent steps─including intramolecular proton transfer, dehydration, cyclization, and dehydroaromatization─facilitate the assembly of the fused heterocyclic scaffold.
View Article and Find Full Text PDFMolecules
July 2025
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Centre for Advanced Materials, Nanjing Tech University, Nanjing 211816, China.
Adipic acid (AA), a pivotal precursor for nylon-6,6 and polyurethane, was synthesized via an innovative catalytic electrocatalytic oxidation strategy in this study. Four distinct MnO/CNT nanocatalysts were prepared by hydrothermal and co-precipitation methods and fabricated into electrodes for the oxidation of cyclohexanol (Cy-OH) in a KSO neutral solution. Comprehensive characterization revealed that the catalytic performance depended on both crystalline phase configuration and manganese valence states.
View Article and Find Full Text PDFJ Chem Theory Comput
July 2025
INSTM, via G. Giusti 9, 50121 Firenze, Italy.
Criegee intermediates (CIs) are pivotal reactive species in atmospheric chemistry, playing a central role in alkene ozonolysis and secondary organic aerosol formation. However, their transient nature and unconventional electronic structure pose a serious challenge to both experimental characterization and theoretical modeling. In this work, we present an integrated and cost-effective computational platform for the accurate simulation of the structure and rotational constants of CIs, based on the Pisa Composite Schemes (PCSs) and localized correction strategies.
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