Article
Chemistry, Physical
Cheri Louise Jacobs, Rodolpho do Aido-Machado, Carmien Tolmie, Martha Sophia Smit, Diederik Johannes Opperman
Summary: Selective oxyfunctionalization of non-activated C-H bonds is a significant challenge in synthetic chemistry. In this study, the biocatalytic hydroxylation of medium-chain n-alkanes by the bacterial enzyme CYP153A71 was characterized. The enzyme was found to convert 1-alkanols to aldehydes, fatty acids, and alpha,omega-diols. The crystal structure of the enzyme bound to octanoic acid provided insights into its regioselectivity and substrate binding orientation.
Article
Materials Science, Biomaterials
Haifeng Wu, Shichao Xu, Peidong Du, Yuanxi Liu, Hui Li, Haijun Yang, Ting Wang, Zhen-Gang Wang
Summary: In this study, a nucleotide-Cu2+ complex capable of catalyzing ortho-hydroxylation reactions resembling those of minimalistic monooxygenases was synthesized and investigated. Experimental and theoretical findings revealed that the catalyst formed a ternary complex intermediate with H2O2 and tyramine substrates through weak interactions, leading to the ortho-hydroxylation of tyramine. Moreover, the Cu2+ bound to nucleotides or oligonucleotides exhibited thermophilic catalytic properties.
JOURNAL OF MATERIALS CHEMISTRY B
(2023)
Article
Microbiology
Wei Xiang, Shan Hong, Yanfen Xue, Yanhe Ma
Summary: Rhodococcus sp. strain CH91 has the ability to use long-chain n-alkanes as its sole carbon source and two new genes (alkB1 and alkB2) encoding AlkB-type alkane hydroxylase were identified. The study found that both alkB1 and alkB2 genes are important for the degradation of C16-C36 n-alkanes, with alkB2 playing a more significant role than alkB1.
Article
Microbiology
Kangli Guo, Anna Hakobyan, Timo Glatter, Nicole Paczia, Werner Liesack
Summary: High NH4+ load inhibits bacterial methane oxidation by competing with CH4 for the active site of pMMO. Methylocystis sp. strain SC2 shows cellular acclimatization response to high NH4+ levels involving stress-responsive proteins, synthesis of compatible solutes, and induction of glutathione metabolism pathway. Increased NH4+ load leads to increased pMMO-based oxidation of NH3 to toxic hydroxylamine, resulting in accumulation of NO2- and N2O.
Article
Chemistry, Multidisciplinary
Hiroto Fujisaki, Masaya Okamura, Shiro Hikichi, Takahiko Kojima
Summary: Fe(ii) complexes with pentadentate ligands, including N-heterocyclic carbene moieties, were immobilized onto perfluorinated mesoporous aluminosilicate. These heterogeneous catalysts exhibited excellent performance and selectivity in alkane hydroxylation and cyclohexene epoxidation using H2O2 as the oxidant in CH3CN solvent.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Chenlu Xie, Eddie Sun, Gang Wan, Jian Zheng, Raghubir Gupta, Arun Majumdar
Summary: We report a unique core-shell nanostructured photocatalyst, silica encapsulated TiO2 decorated with AuPd nanoparticles (TiO2@SiO2-AuPd), which prevents methanol overoxidation and exhibits high selectivity and yield of oxygenates even at high UV intensity. The working principles of this core-shell photocatalyst were also systematically investigated. This design concept was further demonstrated to be applicable for the selective oxidation of other alkanes.
Article
Engineering, Environmental
Yulu Wang, Chun-Yu Lai, Mengxiong Wu, Xuanyu Lu, Shihu Hu, Zhiguo Yuan, Jianhua Guo
Summary: This study showed that increasing copper concentration significantly enhanced the perchlorate reduction rate in a methane-based membrane biofilm reactor, as well as promoted methane oxidation and perchlorate reduction rates through adjusting the abundance of functional genes. A higher copper concentration also increased microbial community diversity and facilitated the synergistic association between methanotrophs and perchlorate reducers.
JOURNAL OF HAZARDOUS MATERIALS
(2022)
Article
Biochemistry & Molecular Biology
Jinia Akter, Tegan P. Stockdale, Stella A. Child, Joel H. Z. Lee, James J. Voss, Stephen G. Bell
Summary: CYP102A1 enzyme can be engineered into a peroxygenase by mutating Thr268Glu, which enhances its hydroxylation activity towards saturated fatty acids and offers the potential for simpler cytochrome P450 systems for selective oxidations. The peroxygenase variant showed similar product distributions as the wild-type enzyme and regioselectively hydroxylated specific positions in the fatty acids tested.
JOURNAL OF INORGANIC BIOCHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Michal Tupec, Martin Culka, Ales Machara, Stanislav Machacek, Daniel Bim, Ales Svatos, Lubomir Rulisek, Iva Pichova
Summary: The study elucidated the key role of auxiliary residues in proton and electron transfer in soluble A9 desaturase by mutating them, resulting in increased substrate hydroxylation activity but inhibited native desaturation activity. Additionally, different reaction products were identified from reactions with different substrates.
COMPUTATIONAL AND STRUCTURAL BIOTECHNOLOGY JOURNAL
(2022)
Article
Chemistry, Physical
Wei Peng, Xiaoyang Qu, Sason Shaik, Binju Wang
Summary: This study deciphers the catalytic cycle of pMMO in the presence of the physiological reductant duroquinol (DQH(2)), revealing that O-2 activation is initiated by the Cu-C(ii)-DQH(-) species. The research also uncovers the important roles of the phenol co-substrate for O-2 activation.
Article
Multidisciplinary Sciences
Wafa Ali Eltayb, Mohnad Abdalla, Amr Ahmed EL-Arabey, Ahmed Boufissiou, Mohammad Azam, Saud I. Al-Resayes, Mahboob Alam
Summary: Researchers used bioinformatics tools and molecular docking studies to analyze the structure of pMMO and its interactions with quinone, duroquinone, and P450 enzymes. They discovered that pMMO can produce methanol without Cu in the presence of quinone and duroquinone, and that pmoB1 interacts with P450. This study highlights the importance of studying the membrane of pMMO for understanding its functions.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2023)
Article
Environmental Sciences
Xuefeng Xia, Douglas Ian Stewart, Lirong Cheng, Yueqiao Liu, Yingying Wang, Aizhong Ding
Summary: n-alkanes in diesel fuel threaten ecological security. The subsurface is a critical layer that affects the biodegradation processes of n-alkanes. Water-table fluctuations have an impact on bacterial community and alkB gene abundance.
JOURNAL OF CONTAMINANT HYDROLOGY
(2022)
Article
Biochemistry & Molecular Biology
Simon Ernst, Almuth Maehrlein, Niklas H. Ritzmann, Steffen L. Drees, Susanne Fetzner
Summary: Many natural products contain N-O functional groups that play a crucial role in biological activity. This study presents three flavoprotein N-hydroxylases that belong to a distinct phylogenetic branch within the GR2-fold FPMOs, expanding the knowledge on the catalytic repertoire of GR2-type FPMOs and providing a basis for the discovery of other nitrogen functionalizing reactions.
Article
Chemistry, Inorganic & Nuclear
Kanako Ueno, Yuri Ishimizu, Hiroshi Fujii
Summary: The solvent effect on the reactivity of oxoiron(IV) porphyrin p-cation radical complexes shows that pentane, hexane, heptane, and tert-butyl methyl ether significantly increase reactivity, while dichloromethane is the worst solvent for this purpose.
INORGANIC CHEMISTRY
(2021)
Article
Biotechnology & Applied Microbiology
Chaemin Lee, Yunha Hwang, Hyun Goo Kang, Seung Jae Lee
Summary: The hydroxylation of methane is crucial in environmental microbiology, and soluble methane monooxygenase (sMMO) plays a significant role in this process. The interaction between MMOH and MMOR, as well as the key residues in MMOR, are important for the electron transfer pathway.
JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Kei Usui, Yuichi Manaka, Wang-Jae Chun, Ken Motokura
Summary: A novel Rh-iodide complex was synthesized through surface reaction, exhibiting high catalytic performance for the one-pot synthesis of silylcarbonate derivatives. The catalyst showed higher efficiency for the hydrosilylation reaction compared to the Rh complex alone on SiO2. Analysis of XAFS and XPS revealed that the catalyst's activity could be attributed to the electron-rich state of Rh and decreased steric hindrance.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Qinglin Li, Cong Fang, Zihao Yang, Bo Yu, Moe Takabatake, Ken Motokura, Xiaoyan Sun, Yong Yang
Summary: A facile N and S dual anions substitution strategy is developed to improve the efficiency and stability of the electrocatalytic nitrogen reduction reaction. The results show that the N and S dual substitution not only changes the electronic properties of the catalyst, but also induces the formation of active sites, thereby enhancing the efficiency of the nitrogen reduction reaction.
Article
Chemistry, Physical
Zhiming Ma, Shiqiang Liu, Nanfang Tang, Tao Song, Ken Motokura, Zhemin Shen, Yong Yang
Summary: The coexistence of Fe nanoclusters and Fe single atoms in N-doped porous carbon can significantly enhance the catalytic performance in the aerobic oxidation of primary amines to imines.
Article
Chemistry, Organic
Ken Motokura, Kaiki Nakao, Yuichi Manaka
Summary: Tetraalkylammonium fluorides exhibit higher catalytic activity for converting CO2 to formic acid, while arylboronic acid can facilitate methanol formation and promote the reduction of formic acid to methanol during CO2 reduction.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Engineering, Chemical
Zhaozhan Wang, Shingo Hasegawa, Ken Motokura, Shaoping Kuang, Yong Yang
Summary: In this study, a single-atom Pd catalyst anchored on a PPh3 built-in porous organic polymer (Pd1@POP) was reported for the telomerization reaction of 1,3-butadiene with methanol. The Pd1@POP catalyst exhibited excellent catalytic activity and selectivity, and could be easily recovered and reused for successive reactions.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Physical
Hiroki Iida, Shinji Kondou, Seiji Tsuzuki, Mao Tashiro, Naoki Shida, Ken Motokura, Kaoru Dokko, Masayoshi Watanabe, Kazuhide Ueno
Summary: Electrochemical separation methods using quinones as CO2 capture agents have attracted significant interest due to their low-energy requirements for near-isothermal CO2 separation. However, the low solubility of quinones in nonaqueous solvents limits their total CO2 carrying capacity in the system. In this study, an ionically modified anthraquinone, [BAQMIM]-[TFSA], was synthesized with significantly improved solubility and high ionic conductivity, allowing for high CO2 carrying capacity and reversible capture and release processes.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Siming Ding, Ken Motokura
Summary: Conventional homogeneous catalyst systems using noble metals generate wastes and have high manufacturing costs. Immobilized metal active centers as heterogeneous catalysts in water have emerged as a promising alternative. This review focuses on recent research on immobilized noble metal catalysts for organic reactions in water and highlights the extensive prospects in this field.
CURRENT OPINION IN GREEN AND SUSTAINABLE CHEMISTRY
(2023)
Article
Chemistry, Physical
Ken Motokura, Ayaka Mizuno, Shingo Hasegawa, Masayuki Nambo, Moe Takabatake, Kenta Suzuki, Yuichi Manaka, Yohei Uemura, Shuntaro Tsubaki, Wang-Jae Chun
Summary: In this study, the ability of in situ-generated bimetallic Ru-Sn particles to catalyze the non-oxidative coupling of methane to C2 species at 500°C was investigated. It was observed that the addition of Sn suppressed coke formation while maintaining methane conversion rate to hydrocarbons, with C2 product selectivity of >99%.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Shingo Hasegawa, Keisuke Nakamura, Kosuke Soga, Kei Usui, Yuichi Manaka, Ken Motokura
Summary: In this study, it was found that cyclic carbonates immobilized on a silica support showed catalytic activity for hydrosilylation, indicating that immobilization on a solid support can convert inactive organic molecules into active and heterogeneous organocatalysts.
Article
Chemistry, Physical
Siming Ding, Yuichi Manaka, Masayuki Nambo, Wang-Jae Chun, Ikuyoshi Tomita, Ken Motokura
Summary: We have developed a mesoporous-silica-supported Pd complex catalyst that promotes the Tsuji-Trost allylation of dicarbonyl compounds with allylic alcohols. By doping the silicate backbone with aluminum, the acidity of the support is increased, leading to enhanced catalytic activity in allylation.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Applied
Ken Motokura, Yukina Nakamura, Moe Takabatake, Kenta Suzuki, Shingo Hasegawa
Summary: The direct alkylation of benzene with branched alkanes was investigated, and it was found that Pt/HT catalyst enhances the reaction between 2-methylhexane and benzene, resulting in the formation of heptylbenzenes. However, the acceleration effect of Pt/HT catalyst is limited when 3-methylhexane is used, and the main product is pentylbenzenes.
Article
Nanoscience & Nanotechnology
Moe Takabatake, Ken Motokura
Summary: This review provides an overview of montmorillonite-based heterogeneous catalysts used for efficient organic reactions. Different types of montmorillonite catalysts, including cation-exchanged and metal-supported catalysts, are discussed. The unique layered structure of montmorillonite allows it to serve as a catalyst support and exhibit strong acidity and stabilizing effects on active species. The use of montmorillonite-based catalysts offers solutions to the separation difficulties encountered with traditional homogeneous catalysts, making it suitable for industrial applications.
Article
Chemistry, Physical
Ria Ayu Pramudita, Kaiki Nakao, Chihiro Nakagawa, Ruopeng Wang, Toshimitsu Mochizuki, Hidetaka Takato, Yuichi Manaka, Ken Motokura
Summary: By using powdered waste silicon wafer as a reducing agent and tetrabutylammonium fluoride as a catalyst, CO2 was successfully reduced to form formic acid with a high yield. The reaction system has potential applications in methanol synthesis and reductive functionalization of amine to formamide.
Article
Chemistry, Multidisciplinary
Yuanyuan Kong, Siming Ding, Koichiro Endo, Kiyotaka Nakajima, Yuichi Manaka, Wang-Jae Chun, Ikuyoshi Tomita, Ken Motokura
Summary: The Rh-catalyzed 1,4-addition reaction of arylboronic acid is crucial in the synthesis of beta-arylcarbonyl compounds. This study immobilized Rh complexes and organic functional groups on mesoporous silica, resulting in significantly improved catalytic activity and yield in water. The catalyst showed broad applicability to a variety of arylboronic acids and enones.
Article
Chemistry, Multidisciplinary
Kei Usui, Yuichi Manaka, Wang-Jae Chun, Ken Motokura
Summary: A novel Rh-iodide complex was synthesized for one-pot synthesis of silylcarbonate derivatives. The catalyst exhibited high activity for hydrosilylation due to the electron-rich state of Rh and decreased steric hindrance.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
