JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2020
·
IF 4.192
Xiaofeng Zhang,Xinqi Xu,Xuemei Yao,Rong Wang,Hengtao Tang,Xin Ju,Liangzhi Li
Ribose-5-phosphate isomerase B is of great importance for biocatalysis and biosynthesis, but the multifunctional residues in active sites hinder the research efforts. This study employed rational design strategies to locate the key residues of RpiB from Ochrobactrum sp. CSL1 (OsRpiB). A single-mutant S9T of a noncontact residue showed 80% activity improvement toward d-allose. A double-mutant S98H/S134H further increased the activity to 3.6-fold. The mutations were analyzed by kinetics and molecular dynamics analyses, indicating that S9T might enhance the substrate binding and catalysis by inducing a steric effect, and S98H/S134H could strengthen both ring opening and binding of d-allose. Though S98H/S134H showed low temperature stability, its potential was explored by isomerizing d-allose to d-psicose with higher conversion and in less reaction time. The findings of this study were beneficial for illustrating the complex functions of key residues in RpiBs and applying OsRpiB in preparing rare sugars.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Shuang Sun,Lijie Zhao,Jirui Yang,Xiaoqi Wang,Xiaoya Qin,Xinhua Qi,Feng Shen
A green, efficient, and facile ball-milling-assisted strategy was proposed to design an SO3H-containing solid acid for biomass valorization, where −SH groups were grafted on a natural clay attapulgite by wet ball milling with 3-mercaptopropyltrimethoxysilane (MTPS), followed by the oxidation of −SH to −SO3H with H2O2 at room temperature. The mechanism of the −SO3H functionalization by the ball-milling process was investigated, and the investigation indicated that the MTPS was grafted on the attapulgite through hydrolysis and condensation, which was induced by the mechanical forces of ball milling. Characterization, including SEM, EDX (energy-dispersive X-ray spectrometry), NH3-TPD, TGA, FT-IR, elemental analysis, and XPS, confirmed the success of −SO3H modification on attapulgite with a total acidity of 1.81 mmol/g. Harsh conditions involving a corrosive sulfonating agent, organic solvent, or high temperature in traditional methods are avoided in the developed approach. The prepared catalyst displayed a high activity toward the transformation of biomass-derived carbohydrates (glucose, fructose, cellobiose, sucrose, starch, and cellulose) into the more valuable chemical 5-hydroxymethylfurfural due to the synergy effect of MgO and −SO3H sites on the catalyst. Moreover, the catalyst showed excellent stability and recyclability for five recycles without loss of activity. This study provides a novel green method for the preparation of an SO3H-containing heterogeneous catalyst, which should have great application potential in other processes of biomass valorization.
✓ 已验证
产品关联
DOI
高影响因子
Biotechnology for Biofuels
·
2020
·Vol. 13
·期 1
·1-13
·
IF 4.815
Chen Jiuzhou,Wang Yu,Guo Xuan,Rao Deming,Zhou Wenjuan,Zheng Ping,Sun Jibin,Ma Yanhe
Background 5-Aminolevulinic acid (5-ALA) is a promising biostimulant, feed nutrient, and photodynamic drug with wide applications in modern agriculture and therapy. Considering the complexity and low yield of chemical synthesis methods, bioproduction of 5-ALA has drawn intensive attention recently. However, the present bioproduction processes use refined glucose as the main carbon source and the production level still needs further enhancement.Results To lay a solid technological foundation for large-scale commercialized bioproduction of 5-ALA, an industrial workhorse Corynebacterium glutamicum was metabolically engineered for high-level 5-ALA biosynthesis from cheap renewable bioresources. After evaluation of 5-ALA synthetases from different sources, the 5-ALA biosynthetic pathway and anaplerotic pathway were rebalanced by regulating intracellular activities of 5-ALA synthetase and phosphoenolpyruvate carboxylase. The engineered biocatalyst produced 5.5 g/L 5-ALA in shake flasks and 16.3 g/L in 5-L bioreactors with a one-step fermentation process from glucose. To lower the cost of feedstock, cheap raw materials were used to replace glucose. Enzymatically hydrolyzed cassava bagasse was proven to be a perfect alternative to refined sugars since the final 5-ALA titer further increased to 18.5 g/L. Use of corn starch hydrolysate resulted in a similar 5-ALA production level (16.0 g/L) with glucose, whereas use of beet molasses caused seriously inhibition. The results obtained here represent a new record of 5-ALA bioproduction. It is estimated that replacing glucose with cassava bagasse will reduce the carbon source cost by 90.1%.Conclusion sThe high-level biosynthesis of 5-ALA from cheap bioresources will brighten the prospects for industrialization of this sustainable and environment-friendly process. The strategy for balancing metabolic flux developed in this study can also be used for improving the bioproduction of other value-added chemicals.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2020
·
IF 4.794
Xiaowei Fang,Ze Wang,Wenli Song,Songgeng Li
In this paper the aldol condensation of furfural (C5) with acetone (C3) over Ca/ZSM-5 was studied with lower dosages of water and acetone as compared to previous studies. It was observed that the formation of CaO over the catalyst is critical to catalyst activity and that the reaction may not occur without water. Although higher quantity of water was favorable for the formation of 4-(2-Furyl)-3-buten-2-one (C8), it was inhibitive for the formation of 1,5-bis-(2-furanyl)-1,4-pentadien-3-one (C13). Highest yields of C8 (38.4 mol%) and C13 (60.2 mol%) were obtained with C3-to-C5 mole ratio of 0.8:1, and water content of 29.7 wt%. The deactivated catalyst was further regenerated by re-loading CaO. An intrinsic kinetic model was established whereby the reaction was first-order dependent on the concentration of each reactant. The formation of 4-(2-furyl)-4‑hydroxy‑butan-2-one (C8-OH), and the C8-OH-to-C8 dehydration were essential steps. The reaction of C8-OH with C5 owned the highest activation energy (41.9 kJ/mol), this step was more sensitive to reaction temperature than those of other steps.
✓ 已验证
产品关联
DOI
高影响因子
Biomass Conversion and Biorefinery
·
2020
·Vol. 11
·期 5
·1931-1941
·
IF 2.602
Tian Xiatian,Qi Benkun,Zhang Shaofeng,Luo Jianquan,Wan Yinhua
5-Hydroxymethylfurfural (HMF) is a promising platform chemical for production of value-added chemicals and fuels. Conversion of abundantly available and cheap sucrose for HMF synthesis was systematically investigated in the present study. Results showed that Lewis acid AlCl 3 is effective in catalytic transformation of sucrose. Combining AlCl 3 with different Brønsted acids, no matter whether they were inorganic acids (HCl, H 2 SO 4 , and H 3 PO 4 ) or organic acids (malic acid, succinic acid, and oxalic acid), or variation of ratio of Lewis acid/Brønsted acid represented by AlCl 3 /HCl, did not change the obtained maximum HMF yields compared with AlCl 3 alone, but shortened the time required to reach the maximum HMF yield. Sucrose conversion in a green reaction media of aqueous γ-valerolactone (GVL) solvent resulted into comparable HMF yields with dimethyl sulfoxide (DSMO)-water system. Addition of monovalent salt NaCl and divalent salt Na 2 SO 4 produced opposite effect with Cl − promoting while SO 4 2− inhibiting HMF production. Furthermore, HMF synthesis from constituent monosaccharides of sucrose and molasses, a by-product from sugar manufacturing process, was also carried out and it was found that an equivmole mixture of glucose and fructose gave rise to almost identical HMF yield to the same mole of sucrose. Molasses, even after chemical pretreatment for removal of certain amount of inorganic salts and color substances, was significantly inferior to synthetic molasses in terms of HMF formation, indicating the complexity and difficulty in chemical valorization of molasses for production of platform molecules.
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Peng Jiang,Yang He,Yiping Zhao,Li Chen
Patients with end-stage renal disease are prone to developing a complication of hyperhomocysteinemia, manifesting as an elevation of the homocysteine (Hcy) concentration in human plasma. However, Hcy as a protein-bound toxin is barely removed by conventional hemodialysis membranes. Here, we report a novel hemodialysis membrane by preparing a bioactive coating of pyridoxal 5′-phosphate (PLP) and adding biocompatible hyperbranched polyglycerol (HPG) brushes to achieve Hcy removal. The dip-applied PLP coating, a coenzyme with a role in Hcy metabolism, dramatically promoted a decrease in the Hcy concentration in human plasma. Moreover, the aldehyde group of PLP had an intrinsic chemical reactivity toward the terminal amino group to immobilize the HPG brushes on the hemodialysis membrane surface. The hierarchical PLP–HPG layer-functionalized membranes had a high efficacy for eliminating Hcy, with a concentration from the initial stage of 150 μmol/L reduced to a nearly normal level of 20 μmol/L in simulated dialysis. By analyzing the impact of HPG brushes with various chain lengths, we found that HPG brushes with a medium length enabled the PLP coating with the bioactive function of Hcy conversion to additionally protect Hcy-attacked target cells by providing excellent hydrophilicity and a dense enough chain volume overlap of the hyperbranched architecture. Simultaneously, the densely packed HPG brushes generated a maximal steric and hydration barrier that significantly improved biofouling resistance against blood proteins. The optimally functionalized membranes showed a clearance of 83.1% urea and 49.6% lysozyme and a rejection of 96.0% bovine serum albumin. The diversely functionalized PLP–HPG layers demonstrate a potential route for a more integrated hemodialysis membrane that can cope with the urgent issue of hyperhomocysteinemia in clinical hemodialysis therapy.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TALANTA
·
2020
·
IF 5.339
Chengji Sui,Qian Wang,Yunlei Zhou,Dingding Zhang,Huanshun Yin,Shiyun Ai
A sensitively homogeneous electrochemiluminescence (ECL) method was developed for 5-hydroxymethylcytosine (5hmC) detection using TiO 2 /MoS 2 /g-C 3 N 4 /GCE as substrate electrode, where g-C 3 N 4 was employed as the ECL active material, the MoS 2 nanosheets were used as co-catalyst, and TiO 2 was adopted as phosphate group capture reagent. To achieve the specific recognition and capture of 5hmC, the covalent reaction between –CH 2 OH and –SH was employed under the catalysis of HhaI methyltransferase, in which, –SH functionalized ferrocenedicarboxylic acid polymer (PFc-SH) was prepared as 5hmC capture reagent and ECL signal quencher. Then, based on the interaction between TiO 2 and phosphate group of 5hmC, the target was recognized and captured on electrode, resulting in a decreased ECL response due to the quenching effect of PFc-SH. Under optimal conditions, the biosensor presented the linear range from 0.01 to 500 nM with the detection limit of 3.21 pM (S/N = 3). The steric effect on electrode surface is a bottle-neck issue restricting devised biosensors advancement. In this work, the reaction between 5hmC and PFc was carried out in the solution, which can avoid steric effect on electrode surface to keep the high activity of enzyme. In addition, the biosensor was successfully applied to detect 5hmC in genomic DNA of chicken embryo fibroblast cells and different tissues of rice seedlings.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Wen Li,Kuncan Wang,Guowu Zhan,Jiale Huang,Qingbiao Li
The chemical transformation of CO2 to value-added chemicals and fuels remains a daunting research challenge, requiring the development of more efficient catalysts. The present work offers highly active integrated nanocatalysts for CO2 hydrogenation to dimethyl ether (DME) through tandem catalysis, that is, Pd/ZnO converts CO2 to methanol, and bio-ZSM-5 further catalyzes methanol dehydration to DME. Notably, the hierarchically porous bio-ZSM-5 with high pore connectivity was prepared by using low-cost rice husk and luffa sponge as biotemplates. The formation of bio-ZSM-5 involved three consecutive steps, including (i) diffusion of precursor species, (ii) confined crystal growth, and (iii) calcination treatment to remove the residual biomass. Interestingly, the obtained bio-ZSM-5 possesses abundant hierarchical porosity, including the intrinsic micropores from ZSM-5 frameworks, the mesopores from intracrystalline void space or pinholes in the intergrown zeolite layers, and the macroscopic channels from the original biomass architecture. It was found that the tetrapropylammonium hydroxide amount and Si/Al ratio were two critical factors affecting the crystallinity and porosity of the bio-ZSM-5. The silicon content in biomass (8.3 wt % in rice husk and 0.016 wt % in luffa sponge) also played a crucial role in the synthesis of bio-ZSM-5. Different spatial configurations of Pd/ZnO and bio-ZSM-5 significantly affected the DME yield, wherein spatial distances between the bio-ZSM-5 and Pd/ZnO components were adjusted by controlling the size of Pd/ZnO or the integration manners. The current results indicated that the closest proximity of the bifunctional catalyst was unfavorable for DME production (selectivity < 3%), because of which low-valent Zn cations from Pd/ZnO could displace the Brønsted acid sites on bio-ZSM-5 by ion exchange, and the powder mixing in the mortar was the best combination configuration of Pd/ZnO and bio-ZSM-5, promoting the CO2 conversion (10.8%) with a DME selectivity of 31% under the reaction of 300 °C and 30 bar. Furthermore, as compared to the traditional ZSM-5 based catalyst, the obtained Pd/ZnO/bio-ZSM-5 bifunctional catalysts showed excellent long-term stability in 60 h on stream with a less amount of coke formed in the spent catalysts.
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Yunpu Wang,Linyao Ke,Yujie Peng,Qi Yang,Yuhuan Liu,Qiuhao Wu,Yujie Tang,Haibin Zhu,Leilei Dai,Zihong Zeng,Lin Jiang,Roger Ruan
In view of the poor selectivity of aromatic hydrocarbons in bio-oil from biomass pyrolysis and the high pressure drop and rapid coking and deactivation of catalyst in industrial scale, a microwave-driven HZSM-5@SiC ceramic foam has been constructed, and applied to the ex-situ catalytic fast pyrolysis of soapstock to improve the content of aromatic hydrocarbons in bio-oil. The effects of different catalysts and heating modes and mass ratios of HZSM-5@SiC ceramic foam to soapstock on the distribution of pyrolysis products have been investigated. In addition, combined with the comparison of microwave and electric heating, the deactivation characteristics of HZSM-5@SiC ceramic foam have been studied. Finally, the process of preparing aromatic oil by microwave-driven catalytic pyrolysis of soapstock was discussed. Experimental results indicate that compared with HZSM-5, HZSM-5@SiC ceramic foam has a higher yield of bio-oil and higher aromatization activity. Under microwave heating, the relative content of aromatic hydrocarbons increases from 25.18% to 100% when the mass ratio of HZSM-5@SiC ceramic foam to soapstock increases from 0:1 to 1:1. Compared with electric heating catalysis, HZSM-5@SiC ceramic foam has the lowest yield of coke under microwave heating. After five consecutive uses, it still maintains more than 90% catalytic activity and has higher stability, which provides a scientific basis for the pilot scale experiments of soapstock catalytic pyrolysis.
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Ying-Bo Zhu,Jia Guo,Yu-Long Ma,Yuan-Yuan Li
The production of high-value-added chemicals from the degradation of real lignin still has been an unresolved issue. In this study, a two-step strategy was proposed to obtain n-hexanol from alkali lignin, and high conversion of alkali lignin and selectivity of n-hexanol were achieved. The deoxygenation performance of the synthesized Ni-HZSM-5 catalyst, modified by Ca, was efficiently improved. At first, through the deoxygenation of alkali lignin via Ni/CaO-HZSM-5, the C–O bonds of the material were broken effectively and 44% degree of deoxygenation (DOD) was obtained. Second, n-hexanol was selectively produced over the Ni/HZSM-5 catalyst from the liquid product obtained by the first step. The efficiency of deoxygenation (DOD) was attained at 71%, and the heat value increased to 51.6 MJ/kg from 19.9 MJ/kg after the two-step strategy. This strategy showed a high catalytic effect to produce n-hexanol from alkali lignin using Ni/CaO-HZSM-5 and Ni/HZSM-5 catalysts and revealed a superior advantage in the hydrodeoxygenation of real lignin to form high additional value chemicals.
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2020
·
IF 3.421
Yang Qu,Yuan Zhao,Shanshan Xiong,Chenguang Wang,Shurong Wang,Lingjun Zhu,Longlong Ma
5-Hydroxymethylfurfural (HMF) and levulinic acid (LA) are two important platform compounds that can be produced by the dehydration of hexoses from hydrolysis of cellulose. In this study, glucose dehydration was catalyzed by the SO42–/ZrO2 catalyst in the NaCl–THF/H2O biphasic solvent system. Complete conversion of glucose was achieved at 160 °C. The highest HMF yield and LA yield were 61.84% and 29.68%, respectively. The results showed that the conversion and product distribution were influenced by catalyst acidity, solvent composition, temperature, and time. The SO42– load greatly changed the acidity of the catalyst, thus affecting the product distribution. By changing the composition of the catalyst and the biphasic solvent system, different yields of HMF and LA could be obtained, so as to realize directional synthesis of the target products.
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Li Wang,Shengxian Liu,Wenjing Du,Tongyi Dou,Changhai Liang
5-Cyanovaleramide (5-CVAM) is an important intermediate of a herbicide and chemical raw material. Herein, we found a novel nitrile hydratase from the strain Rhodococcus erythropolis CCM2595, exhibiting high regioselectivity with higher substrate specificity toward dinitriles than mononitriles. In the past, the strain was shown to degrade only phenol, hydroxybenzoate, p-chlorophenol, aniline, and other aromatic compounds. In our study, 20 mM adiponitrile was completely consumed within 10 min with 95% selectivity to 5-CVAM and 5% selectivity to adipamide. In addition to its high regioselectivity, our recombinant Escherichia coli showed a higher substrate tolerance of up to 200 mM adiponitrile even after 3 h when compared with two reported strains with their cyano-tolerance concentrations of up to 100 mM, which is considered to be the highest cyano-tolerance. Such a robust biocatalyst is a desirable attribute of a biocatalyst intended for use in commercial applications of 5-CVAM.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）