- Ru/P-containing porous biochar-efficiently catalyzed cascade conversion of cellulose to sorbitol in water under medium-pressure H2 atmosphere
-
This paper discloses a simple and productive strategy for the preparation of biochar-based bifunctional catalysts. In this strategy, very cheap bamboo powder is thermally carbonized to yield P-containing porous biochars (PBCs) by the activation of concentrated phosphoric acid (H3PO4), and the latter can be transformed into the target catalysts via loading Ru nanometer particles (NPs) on them (marked as Ru/PBCs). A series of characterizations and measurements support that PBCs have stable and rich micro-meso pores and small strong acidic protons (0.100.28 mmol¢g11) attributable to the grafted and/or skeleton phosphorus groups, as well as a strong affinity to β-1,4-glycosidic bonds, thus exhibiting a good acid catalytic activity for the hydrolysis of cellulose to glucose. More importantly, they are excellent acidic supports for the loading of Ru NPs owing to high BET surface area, which can give the loaded Ru NPs uniform and narrow distribution (16 nm). The resulting bifunctional Ru/PBCs catalysts possess excellent hydrolytic hydrogenating activity for the one-pot cascade conversion of cellulose and the optimized conditions can achieve ca. 89% hexitol yield with 98% sorbitol selectivity under relatively mild conditions. This work provides a good example for the preparation of biomass-derived bifunctional catalysts and their applications in biorefinery.
- Chen, Shuainan,Fu, Zaihui,Jiang, Dabo,Liu, Yachun,Mao, Feng,Wan, Feifei,Xiong, Manman,Yang, Long,Zhang, Chao,Zhang, Qiao
-
p. 1026 - 1035
(2020/09/22)
-
- High Yielding Acid-Catalysed Hydrolysis of Cellulosic Polysaccharides and Native Biomass into Low Molecular Weight Sugars in Mixed Ionic Liquid Systems
-
Ionic media comprising 1-butyl-3-methylimidazolium chloride and the acidic deep eutectic solvent choline chloride/oxalic acid as co-solvent-catalyst, very efficiently convert various cellulosic substrates, including native cellulosic biomass, into water-soluble carbohydrates. The optimum reaction systems yield a narrow range of low molecular weight carbohydrates directly from cellulose, lignocellulose, or algal saccharides, in high yields and selectivities up to 98 %. Cellulose possesses significant potential as a renewable platform from which to generate large volumes of green replacements to many petrochemical products. Within this goal, the production of low molecular weight saccharides from cellulosic substances is the key to success. Native cellulose and lignocellulosic feedstocks are less accessible for such transformations and depolymerisation of polysaccharides remains a primary challenge to be overcome. In this study, we identify the catalytic activity associated with selected deep eutectic solvents that favours the hydrolysis of polysaccharides and develop reaction conditions to improve the outcomes of desirable low molecular weight sugars. We successfully apply the chemistry to raw bulk, non-pretreated cellulosic substances.
- Bodachivskyi, Iurii,Kuzhiumparambil, Unnikrishnan,Bradley G. Williams
-
p. 1316 - 1324
(2019/11/11)
-
- Cloning, expression and biochemical characterization of a GH1 β-glucosidase from Cellulosimicrobium cellulans
-
β-Glucosidase plays an important role in the degradation of cellulose. In this study, a novel β-glucosidase ccbgl1b gene for a glycosyl hydrolase (GH) family 1 enzyme was cloned from the genome of Cellulosimicrobium cellulans and expressed in Escherichia coli BL21 cells. The sequence contained an open reading frame of 1494 bp, encoded a polypeptide of 497 amino acid residues. The recombinant protein CcBgl1B was purified by Ni sepharose fastflow affinity chromatography and had a molecular weight of 57 kDa, as judged by SDS-PAGE. The optimum β-glucosidase activity was observed at 55 °C and pH 6.0. Recombinant CcBgl1B was found to be most active against aryl-glycosides p-nitrophenyl-β-D-glucopyranoside (pNPβGlc), followed by p-nitrophenyl-β-D-galactopyranoside (pNPβGal). Using disaccharides as substrates, the enzyme efficiently cleaved β-linked glucosyl-disaccharides, including sophorose (β-1,2-), laminaribiose (β-1,3-) and cellobiose (β-1,4-). In addition, a range of cello-oligosaccharides including cellotriose, cellotetraose and cellopentaose were hydrolysed by CcBgl1B to produce glucose. The interaction mode between the enzyme and the substrates driving the reaction was modelled using a molecular docking approach. Understanding how the GH1 enzyme CcBgl1B from C. cellulans works, particularly its activity against cello-oligosaccharides, would be potentially useful for biotechnological applications of cellulose degradation.
- Yuan, Ye,Xu, Fenghua,Yao, Jianzhuang,Hu, Yanho,Wang, Jiao,Zhao, Tianjiao,Zhou, Yifa,Gao, Juan
-
p. 362 - 371
(2017/11/03)
-
- A solvent-free, one-step synthesis of sulfonic acid group-functionalized mesoporous organosilica with ultra-high acid concentrations and excellent catalytic activities
-
We demonstrate herein a novel solvent-free technique for the synthesis of sulfonic acid group-functionalized mesoporous organosilica, which was achieved from the self-assembly of a block copolymer template using mercaptopropyltrimethoxysilane (MPTS) and tetramethoxysilane (TMOS) under melting conditions without using additional solvents and subsequent condensation at high temperature (up to 140 °C). The resultant samples were designated as SMS-xs, where x stands for molar ratio of MPTS/(MPTS + TMOS). SMS-xs have relatively large BET surface areas, highly cross-linked frameworks, and abundant and uniform mesopores with wormhole-like characteristics. Interestingly, MPTS could be used as the solo precursor to prepare mesoporous organosilica (SMS-1.0), which had controllable acidity and an ultra-high concentration of sulfur (5.51 mmol g-1, the highest acid density to date), which was even higher than those of commercial Amberlyst 15 (4.7 mmol g-1), HS-JLU-20-0.8 (4.61 mmol g-1) and sulfonated carbon (CH0.30O0.33S0.16, 4.90 mmol g-1). These structural characteristics give SMS-xs excellent activities and good reusability in biomass conversions and fine chemicals synthesis, which are much better than various solid acids, such as Amberlyst 15, H-form USY zeolite, and sulfonic acid group-functionalized ordered mesoporous silica.
- Wu, Qin,Liu, Fujian,Yi, Xianfeng,Zou, Yongcun,Jiang, Lilong
-
p. 1020 - 1030
(2018/03/13)
-
- Hydrolysis of cellulose to glucose over carbon catalysts sulfonated via a plasma process in dilute acids
-
Herein, we reported a novel plasma-sulfonation process for carbon materials in dilute sulfuric acid within a few tens of minutes. The total acidic and -SO3H densities of the sulfonated carbon were 4.4 mmol g-1 and 2.2 mmol g-1, respectively. The glucose selectivity during cellulose hydrolysis using a sulfonated carbon catalyst was 83.9% and retained 98% of its performance after recycling.
- Li, Oi Lun,Ikura, Ryuhei,Ishizaki, Takahiro
-
p. 4774 - 4777
(2017/10/23)
-
- Design and synthesis of micro-meso-macroporous polymers with versatile active sites and excellent activities in the production of biofuels and fine chemicals
-
Micro-meso-macroporous polymers (MOPs) grafted with versatile functional groups, such as sulfonate, amine, triazole, pyridine, strong acidic ionic liquids and triphenylphosphine, were synthesized by in situ cross-linking of different functional molecules with 1,4-bis(chloromethyl)benzene in the presence of Lewis acid catalysts without using additional templates. The resultant hyper-cross-linked nanoporous polymers show unique characteristics such as large BET surface areas (up to 1523 m2 g-1), abundant micro-meso-macropores (4.5-131 nm), and tunable and versatile active sites (acid, base and palladium). These functional polymers exhibit excellent activities and good reusability in biomass conversions, cross-coupling reactions and condensation. The catalytic activities are much better than those of various conventional catalysts such as H3PW12O40, SBA-15-SO3H, Amberlyst 15, and mesoporous H-ZSM-5 Pd/C and even as comparable as those of homogeneous H2SO4 and HCl in the depolymerization of crystalline cellulose into fine chemicals and towards transesterification to biodiesel. This work highlights a low cost route to the synthesis of solid catalysts based on functional nanoporous polymers for catalyzing the production of clean biofuels and fine chemicals.
- Liu, Fujian,Liu, Chen,Kong, Weiping,Qi, Chenze,Zheng, Anmin,Dai, Sheng
-
p. 6536 - 6544
(2016/12/16)
-
- Catalytic conversion of cellulose to hexitols with mesoporous carbon supported Ni-based bimetallic catalysts
-
Robust and highly active Ni-based bimetallic catalysts supported on mesoporous carbon have been developed for catalytic conversion of cellulose to hexitols, over which the maximum hexitol yield reached 59.8%. The Royal Society of Chemistry 2012.
- Pang, Jifeng,Wang, Aiqin,Zheng, Mingyuan,Zhang, Yanhua,Huang, Yanqiang,Chen, Xiaowei,Zhang, Tao
-
scheme or table
p. 614 - 617
(2012/05/20)
-
- A study on chemical constituents and sugars extraction from spent coffee grounds
-
Spent coffee grounds (SCG), the residual materials obtained during the processing of raw coffee powder to prepare instant coffee, are the main coffee industry residues. In the present work, this material was chemically characterized and subsequently submitted to a dilute acid hydrolysis aiming to recover the hemicellulose sugars. Reactions were performed according to experimental designs to verify the effects of the variables H2SO 4 concentration, liquid-to-solid ratio, temperature, and reaction time, on the efficiency of hydrolysis. SCG was found to be rich in sugars (45.3%, w/w), among of which hemicellulose (constituted by mannose, galactose, and arabinose) and cellulose (glucose homopolymer) correspond to 36.7% (w/w) and 8.6% (w/w), respectively. Optimal conditions for hemicellulose sugars extraction consisted in using 100 mg acid/g dry matter, 10 g liquid/g solid, at 163 °C for 45 min. Under these conditions, hydrolysis efficiencies of 100%, 77.4%, and 89.5% may be achieved for galactan, mannan, and arabinan, respectively, corresponding to a hemicellulose hydrolysis efficiency of 87.4%.
- Mussatto, Solange I.,Carneiro, Livia M.,Silva, Jo?o P.A.,Roberto, Inês C.,Teixeira, José A.
-
experimental part
p. 368 - 374
(2011/06/22)
-
- A study of the acid-catalyzed hydrolysis of cellulose dissolved in ionic liquids and the factors influencing the dehydration of glucose and the formation of humins
-
An investigation was carried out into the hydrolysis of cellulose dissolved in 1-ethyl-3-methylimidazolium chloride ([Emim][Cl]) and 1-butyl-3- methylimidazolium chloride ([Bmim][Cl]) catalyzed by mineral acids. Glucose, cellobiose, and 5-hydroxymethylfurfural (5-HMF) were observed as the primary reaction products. The initial rate of glucose formation was determined to be of first order in the concentrations of dissolved glucan and protons and of zero order in the concentration of water. The absence of a dependence on water concentration suggests that cleavage of the β-1,4-glycosidic linkages near chain ends is irreversible. The apparent activation energy for glucose formation is 96kJmol-1. The absence of oligosaccharides longer than cellobiose suggests that cleavage of interior glycosidic bonds is reversible due to the slow diffusional separation of cleaved chains in the highly viscous glucan/ionic liquid solution. Progressive addition of water during the course of glucan hydrolysis inhibited the rate of glucose dehydration to 5-HMF and the formation of humins. The inhibition of glucose dehydration is attributed to stronger interaction of protons with water than the 2-OH atom of the pyranose ring of glucose, the critical step in the proposed mechanism for the formation of 5-HMF. The reduction in humin formation associated with water addition is ascribed to the lowered concentration of 5-HMF, since the formation of humins is suggested to proceed through the condensation polymerization of 5-HMF with glucose.
- Dee, Sean J.,Bell, Alexis T.
-
experimental part
p. 1166 - 1173
(2012/05/04)
-
- Oleic acid-enhanced dissolution of cellulose in high-temperature water
-
This paper reports, for the first time, the enhanced dissolution of cellulose in subcritical water by addition of a fatty acid. Simply adding oleic acid dramatically promoted the dissolution of cellulose. High-pressure in-situ observation showed that cellulose dissolved in high-temperature water at approximately 500 K, which is 70 K lower than without oleic acid. The yield of oligo and monosaccharides with oleic acid at 473 K was seven times higher than without oleic acid.
- Minami, Kimitaka,Goto, Shiori,Atashfaraz, Mehrnoosh,Togashi, Takanari,Arita, Toshihiko,Hojo, Daisuke,Takami, Seiichi,Adschiri, Tadafumi
-
experimental part
p. 415 - 419
(2012/03/26)
-
- The kinetics of p-nitrophenyl-β-d-cellobioside hydrolysis and transglycosylation by Thermobifida fusca Cel5Acd
-
The hydrolysis of p-nitrophenyl-β-1,4-cellobioside (pNP-G2) by the catalytic domain of the retaining-family 5-2 endocellulase Cel5A from Thermobifida fusca (Cel5Acd) was studied. The dominant reaction pathway involves hydrolysis of the aglyconic bond, producing cellobiose (G2) and a 'reporter' species p-nitrophenol (pNP), which was monitored spectrophotometrically to track the reaction. We also detected the production of cellotriose (G3) and p-nitrophenyl-glucoside (pNP-G1), confirming the presence of a competing transglycosylation pathway. We use a mechanistic model of hydrolysis and transglycosylation to derive an expression for the rate of pNP-formation as a function of enzyme concentration, substrate concentration, and several lumped kinetics parameters. The derivation assumes that the quasi-steady-state assumption (QSSA) applies for three intermediate species in the mechanism; we determine conditions under which this assumption is rigorously justified. We integrate the rate expression and compare its integral form to pNP-versus-time data collected for a range of enzyme and substrate concentrations. The integral comparison gives a stringent test of the mechanistic model, and it serves to quantify the lumped kinetics parameters with good statistical precision, particularly a previously unidentified parameter that determines the selectivity of hydrolysis versus transglycosylation. The integrated rate expression accounts well for pNP-versus-time data under all circumstances we have investigated.
- Dingee, John W.,Anton, A. Brad
-
scheme or table
p. 2507 - 2515
(2011/01/04)
-
- Labeling and purification of cellulose-binding proteins for high resolution fluorescence applications
-
The study of enzymatic reactions through fluorescence spectroscopy requires the use of bright, functional fluorescent molecules. In the case of proteins, labeling with fluorescent dyes has been carried out through covalent reactions with specific amino ac
- Moran-Mirabal, Jose M.,Corgie, Stephane C.,Bolewski, Jacob C.,Smith, Hanna M.,Cipriany, Benjamin R.,Craighead, Harold G.,Walker, Larry P.
-
experimental part
p. 7981 - 7987
(2010/04/06)
-