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31.
The production cost of cellulolytic enzymes is a major contributor to the high cost of ethanol production from lignocellulosics
using enzymatic hydrolysis. The aim of the present study was to investigate the cellulolytic enzyme production ofTrichoderma reesei Rut C 30, which is known as a good cellulase secreting micro-organism, using willow as the carbon source. The willow, which
is a fast-growing energy crop in Sweden, was impregnated with 1–4% SO2 and steam-pretreated for 5 min at 206°C. The pretreated willow was washed and the wash water, which contains several soluble
sugars from the hemicellulose, was supplemented with fibrous pretreated willow and used for enzyme production. In addition
to sugars, the liquid contains degradation products such as acetic acid, furfural, and 5-hydroxy-methylfurfural, which are
inhibitory for microorganisms. The results showed that 50% of the cellulose can be replaced with sugars from the wash water.
The highest enzyme activity, 1.79 FPU/mL and yield, 133 FPU/g carbohydrate, was obtained at pH 6.0 using 20 g/L carbon source
concentration. At lower pHs, a total lack of growth and enzyme production was observed, which probably could be explained
by furfural inhibition. 相似文献
32.
Franco Gatta Maria Rosaria Del Giudice Luciano Di Simone Guido Settimj 《Journal of heterocyclic chemistry》1980,17(5):865-868
A new synthesis of 7-chloro-2,3-diamino-5-phenyl-3H-1,4-benzodiazepines is described, which allows for the preparation of compounds bearing the same or different substituents at the 2 and 3 positions, starting from 2-amino-7-chloro-3-hydroxy-5-phenyl-3H-1,4-benzodiazepines. 相似文献
33.
Fabrizio Melani Lucia Cecchi Giovanna Palazzino Guido Filacchioni 《Journal of heterocyclic chemistry》1986,23(1):173-176
Following our reports on synthetic tricyclic analogues of antitumor anthramycin the synthesis of some isomers pyrazolo[4,5-d]- and pyrazolo[4,5-c][1]benzazepine derivatives is reported. 相似文献
34.
Zhang JJ Sheng TL Hu SM Xia SQ Leibeling G Meyer F Fu ZY Chen L Fu RB Wu XT 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(16):3963-3969
The first successful attempt to construct 3D supramolecular frameworks with high-nuclear 3d-4f heterometallic clusters as a node is reported. The self-assembly of Ln3+, Cu2+ and amino acid in solution leads to the formation of two polymers, 35-nuclear complex [Sm6Cu29] 1 with a primitive cubic net-like structure and 36-nuclear complex [Nd6Cu30] 2 with a face-centred cubic network type structure. Glycine and L-proline, respectively, were used as ligands. It should be noted that 2 has a chiral framework. X-ray structure analyses show that 1 crystallizes in the triclinic P1 space group (a=19.6451(8), b=20.4682(8), c=20.7046(8) A, alpha=89.453(1), beta=66.290(1), gamma=68.572(1) degrees, V=7003.0(5) A3 and Z=1) and 2 belongs to the cubic P2(1)3 space group (a=b=c=32.4341(3) A, V=34 119.7(5) A3 and Z=4). Both complexes utilize Ln6Cu24 octahedral clusters as nodes and trans-Cu(amino acid)2 groups as bridges. Electrical conductivity measurements reveal that both polymers behave as semiconductors. 相似文献
35.
The binding of a chiral quaternary ammonium ion to a cyclopeptide containing aromatic amino acid subunits is affected not only by the configuration of the cation but also by the configuration of the chiral counterion. Analysis of the binding equilibria shows that complex formation involves interaction of the whole ion pair with the host indicating that steric requirements of the anion influence complex geometry and stability. 相似文献
36.
In this paper some synthetic procedures to obtain (η6-arene)metal derivatives are reviewed. The metal-atom-arene-vapor co-condensation technique is the most appropriate to generate complexes of polycyclic aromatic hydrocarbons or heterocycles. As far as the aluminium halide-mediated synthesis is concerned, two classes of reaction are observed. When AlX3 is used with a metal halide in the presence of an aromatic hydrocarbon in the absence of any reducing agent, AlX3 can function as a dehalogenating agent, to give ionic compounds of general formula [M(η6-arene)n](AlX4)m, or it can add across the M---X bond with formation of M(μ-X)nAlX4−n systems. In both cases the metal displays its typical oxidation state. However, the use of AlX3 in combination with aluminium (the Fischer-Hafner reducing system) affords ionic or covalent low-oxidation-state metal(η6-arene) complexes. Attention is focused on our most recent results concerning the synthesis, properties and reactivity of η6-arene derivatives of Group 4 and 5 elements, showing, inter alia, the first example of a tetraarylborate anion behaving as a 12-electron donor to one metal atom and low-valent η6-arene compounds as useful reagents in the inorganic and coordination chemistry of the corresponding metal in nonaqueous systems. 相似文献
37.
Chromium trioxide oxidation of 1-phenylisochroman-4-spiro-1′-cyclopentane (Ia) in acetic acid led to the expected 1-(2-benzoylphenyl)cyclopentanecarboxylic acid (IIa), while its 6,7-dimethoxy analogue Ib and 6,7-dimethoxy-1-phenylisochroman-4-spiro-4′-(1′-methyl)piperidine (Ic) under the same conditions gave a mixture of their related 1-hydroxy derivatives VIIIb and VIIIc and of the p-benzoquinones, 1-benzoyloxymethyl-1-(2,5-dioxo-4-methoxyphenyl)cyclopentane (IXb) and 1-benzoyloxymethyl-1-(2,5-dioxo-4-methoxyphenyl)-1-methylpiperidine (IXc). Cyclization of Ila with hydrazine or monomethylhydrazine led to the 5-spiro-substituted 1-phenyl-3,5-dihydro-4H-2,3-benzodiazepin-4-ones IIIa or XIa. 相似文献
38.
Guido Galliani Diego Monti Giovanna Speranza Paolo Manitto 《Tetrahedron letters》1984,25(52):6037-6040
Bilin-1,19(21H,24H)-diones interact with O2·- in DMSO giving rise to adducts showing charge-transfer character. This reaction can be reversed by addition of O2·- consuming compounds. The O2·-biliverdin dimethyl ester adduct collapses partially to 10-oxobilirubin dimethyl ester when treated with thiourea and 2-mercaptoethanol. 相似文献
39.
Hay DN Rickert PG Seifert S Firestone MA 《Journal of the American Chemical Society》2004,126(8):2290-2291
The synthesis and purification of a poly(N-isopropylacrylamide)-lipid conjugate and its use in the preparation of a thermoresponsive lipid mesophase is described. Specifically, poly(N-isopropylacrylamide) with a single carboxyl group at one end was activated with dicyclohexylcarbodiimide/N-hydroxysuccinimide to form an active ester. This N-hydroxysuccinimide ester was then used to form a dimyristoyl-sn-glycero-3-phosphoethanolamine conjugate with poly(N-isopropylacrylamide) via an amide bond, rendering the conjugate amphiphilic. Quaternary phases comprising the conjugate, a phosopholipid, dimyristoylphosphatidylcholine, and a cosurfactant, N,N-dimethyldodecylamine-N-oxide, dispersed in water were found to self-assemble at room temperature to form liquid crystalline gels, adopting an expanded lamellar structure. A modest increase in temperature triggered the reversible conversion of the aggregate to a collapsed lamellar structure, while a modest reduction in temperature resulted in its conversion to a nonlamellar phase. The phases were characterized by polarized optical microscopy and small-angle X-ray scattering (SAXS). 相似文献
40.
Guido Kickelbick Dieter Rutzinger Thomas Gallauner 《Monatshefte für Chemie / Chemical Monthly》2002,133(8):1157-1164
Summary. Hexadentate ligands were formed by the reaction of primary dimethylaminoethyl- or methoxyethylamines with formaldehyde. The
resulting N, N′, N″-functionalized hexahydro-1,3,5-triazines contain pending amino or ether functionalities which are able to coordinate to
metals in addition to the ring nitrogen atoms. Both ligands were reacted with CuBr, and novel tricopper clusters were isolated
and characterized by X-ray structure analysis. In these compounds a ring nitrogen atom, the pending amino or ether functionality,
and two bridging bromine atoms coordinate each of the copper atoms.
Received January 22, 2002; accepted (revised) March 22, 2002 相似文献