ACS Sustainable Chemistry & Engineering
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2023
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IF 8.4
Zhihao Zhang,Jiayu Xue,Zewen Sun,Jiale Wang,Guochao Xu,Ye Ni
Hydrogen-borrowing redox-neutral cascade reactions are promising for the synthesis of lactones from the perspective of sustainable chemistry. In this study, a novel NADPH-dependent Baeyer–Villiger monooxygenase AjBVMO was identified from Acinetobacter johnsonii with a specific activity of 0.96 U·mg–1 in the oxidation of cyclohexanone into ε-caprolactone. To achieve cofactor matching, NADP+-dependent KpADHT215V and CgKR1 with high oxidative activities toward cyclohexanol and 1,6-hexanediol were constructed for developing “substrate-supplied” and “product-convergent” hydrogen-borrowing redox-neutral cascade reactions. The effects of buffer systems on the activities and spontaneous hydrolysis of ε-caprolactone and the ratios of ADHs and BVMO on the conversion rates were explored. In the “substrate-supplied” system employing KpADHT215V and AjBVMO, as high as 68.6 mM ε-caprolactone could be obtained from 100 mM cyclohexanol, with a maximum TOF of 7.2 min–1 and a TTN of 337. In the “product-convergent” system employing CgKR1 and AjBVMO, 115.1 mM ε-caprolactone was produced from 100 mM cyclohexanone, with a maximum TOF of 5.7 min–1 and a TTN of 757. The product-convergent system is more efficient than the substrate-supplied system. Moreover, these two redox-neutral cascade systems could also be applied in the synthesis of lactones with different chain lengths such as γ-butyrolactone and δ-valerolactone. This study established efficient redox-neutral cascade systems for the synthesis of lactones featuring a high atomic economy with only H2O as a byproduct.
研究领域:
生物化学
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可持续化学
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酶工程
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2023
·Vol. 140
·期 17
·e53762
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IF 3
Guiying Tian,Huiqing Wang,Yuanyuan Song,Jun Xiang,Yiran Ying,Xurui Han,Songbo Wang,Lei Zhang,Jianping Zhang,Na Tang
Lactide is the crucial intermediate for polylactic acid (PLA) synthesis via ring-open polymerization, but it suffers low yield and low purity induced by racemization reaction. In this work, we have developed a zinc oxide-creatinine (ZnO-CR) hybrid catalyst, which offers high yield (the distilled lactide yield and pure l -lactide yield are 95.73% and 61.64%) and high purity (81.53%) for green l -lactide synthesis at the cyclization temperature of 240°C. Furthermore, NMR and HPLC results show that CR addition significantly restrains the racemization by reducing α-proton abstraction, where guanidine derived from the CR plays a main catalytic role to provide a tight association with the carbonyl oxygen in the carboxyl of L n A oligomers. Therefore, carbonyl-carbon with the enhanced electrophilicity is easier being attacked by a hydroxyl terminal of L n A oligomers, leading to high yield and high purity for lactide synthesis.
研究领域:
化学工程
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材料科学
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催化化学
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产品关联
DOI
高影响因子
Journal of Materials Chemistry A
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2025
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IF 9.5
Xiaohao Liu,Dali Han,Jinming Xia,Dongxu Yan,Rui Diao,Fenglei Qi,Zhenyu Wang,Lei Yang,Xiang Wu,Peiyong Ma,Ying Zhang
Nanopore-confining strategy is an effective way to inhibit catalyst sintering and improve catalytic performance. However, the expensive material precursors and complex preparation process greatly limit the scale utilization of this particularly structured catalyst. Herein, nanopore-confined catalysts (Ni@PAC) with adjustable active species were successfully prepared by a very simple method exploiting the characteristics of phosphoric acid-activated biochar (PAC). The abundant phosphorous functional groups in PAC confined Ni well in pores and significantly inhibited sintering through the spatial-confined effect of nanopore. Moreover, the evolution and migration of P functional groups can be regulated by changing the reduction temperature, and the modulation of active species of Ni metal or nickel phosphide can be achieved. Using biomass-based levulinic acid hydrogenation as the probe reaction, it was found that the catalytic activity of 20Ni@PAC-600 was one order of magnitude higher than that of the non-phosphated 20Ni/ZAC-600 catalyst, and γ-valerolactone could be selectively prepared at near atmospheric pressure (1 bar). The formation of Ni2P and the spatial-confined effect of nanopore could be the main reasons for the high catalytic activity.
研究领域:
催化化学
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生物质转化
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材料科学
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产品关联
DOI
高影响因子
ChemCatChem
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2023
·Vol. 15
·期 21
·e202300852
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IF 4.5
Mengyang Liu,Bin Gu,Jingmei Li,Huangzhao Wei,Weiyang Xue,Yukun Jiang,Chenglin Sun
Graphical Benefiting from the synergistic effect of supported bimetallic CeFe which induces higher metal dispersion and higher content of reactive oxygen, and the buffering effect of resin-derived-carbon on free radicals, the aerobic oxidation of cyclohexanone to ϵ-caprolactone (ϵ-CL) is performed over CeFe@RDC-x, and the catalytic efficiency is significantly improved. Especially, when solvent-free and green solvents (such as ethyl acetate) are used, excellent catalytic conversion effects are achieved. Upgrading cyclohexanone to ϵ-caprolactone (ϵ-CL) is of great importance to the synthesis of high value-added downstream chemicals and the reduction of foam plastic. The catalytic synthesis of ϵ-CL from cyclohexanone through O 2 /aldehyde method is an environmentally benign one-pot tandem reaction without using peroxy acid, balancing the requirements of safety and efficiency. However, due to lack of elaborate design and collaboration of multiple active sites for catalysts, the catalytic efficiency of O 2 /aldehyde method still remains to be improved. Herein, a pitaya-like catalyst (CeFe@RDC-3) with Ce and Fe highly dispersed on resin-derived-carbon is synthesized through high temperature self-assembly. On this bimetallic catalyst, high yield (97 %) of ϵ-CL is achieved through aerobic oxidation of cyclohexanone with only 1.5 equivalent benzaldehyde. Moreover, considerable yields of ϵ-CL, 88.3 % and 74.7 %, respectively, are also obtained over CeFe@RDC-3 with green solvent (EtOAc) or even without solvent. No loss of activity is observed after five successive cycles, demonstrating high stability of CeFe@RDC-3. The mechanism study reveals that the high performance of CeFe@RDC-3 is ascribed to the Ce−Fe bimetallic synergy, uniform metal dispersion, abundant active oxygen and stabilizing effect of resin-derived-carbon to free radicals. This work provides prospect for a green, safe and low-cost strategy for Baeyer-Villiger process.
研究领域:
材料科学
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催化化学
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环境科学
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2025
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IF 7.3
Xinqi Xu,Shumin Wang,Yaqun Zhong,Juanjuan Yang,Lian Xu,Bingmei Su,Juan Lin
Whole-cell redox-neutral cascade reactions are promising for the sustainable synthesis of bulky lactones. In this study, the cyclohexanone monooxygenase from Acinetobacter sp. NCIMB 9871 (CHMOAc) was rationally designed based on enhancing product release and consensus sequence design to enhance the activity and stability of the enzyme. A four-point mutant MU4 (G14A/A43G/M400L/F432I) showed improved activity and stability for the oxidation of cyclohexanone to ε-caprolactone at a high substrate loading. A newly NADPH-dependent alcohol dehydrogenase from Pseudomonas monteilii (PmADH) with high cyclohexanol oxidation activity was introduced for constructing the redox-neutral cascade for the synthesis of ε-caprolactone from cyclohexanol. To improve the intracellular environment for cascade synthesis of ε-caprolactone, CRISPR/Cas9-mediated strong promoter insertion to the endogenous catalase gene katE in the NADP self-sufficient Escherichia coli strain BK-1 (Ptrc-nadK/Ptrc-pncB) was done for mitigating the oxidative stress to obtain the strain E. coli BKE-3 harboring MU4 and PmADH. Finally, 776 mM cyclohexanol could be converted into ε-caprolactone by the BKE-3 whole-cell catalytic system with a >99% conversion rate without cyclohexanone accumulation, which was the highest record for the redox-neutral cascade synthesis of ε-caprolactone. The BKE-3 whole-cell catalytic system also showed high efficiency for the synthesis of various lactones. This work provides an efficient redox-neutral catalytic platform for the sustainable synthesis of lactones featuring high substrate loading and atomic economy.
研究领域:
生物催化
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酶工程
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合成生物学
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生物过程工程
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蛋白质工程
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代谢工程
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工业生物技术
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DOI
高影响因子
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