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1.
Xylanase-induced reduction of chlorine dioxide consumption during elemental chlorine-free bleaching of different pulp types 总被引:4,自引:0,他引:4
Andreas M. Madlala Sadhvir Bissoon Suren Singh Lew Christov 《Biotechnology letters》2001,23(5):345-351
The potential of crude xylanase from Thermomyces lanuginosus and Xylanase P (a commercial xylanase) was evaluated in bleaching of various paper pulp types. Xylanases released chromophores and reducing sugars and decreased kappa number of pulps. Chlorine-bleached, alkali-extracted bagasse and post-oxygen kraft pulps, pretreated with enzymes, gained over 5 brightness points over controls. Biobleaching of soda-aq pulp with Xylanase P produced chlorine dioxide savings of up to 30% or 4.5 kg chlorine dioxide t–1 pulp. 相似文献
2.
Residual lignin studies of laccase-delignified kraft pulps 总被引:9,自引:0,他引:9
The delignification of chemical pulps with laccase and
-hydroxybenzotriazole was explored employing a pre- and post-O2 delignified softwood draft pulp. The delignification properties of laccase were shown to be improved with
-hydroxybenzotriazole was used as a mediator instead of 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid). Analysis of the structure of residual lignin before and after laccase/
-hydroxybenzotriazole treatment indicated that the biobleaching system oxidizes the phenolic component of lignin and that the residual lignin is demethylated and significantly enriched in carboxylic acid groups. 相似文献
3.
Some properties of eucalyptus kraft pulp treated with xylanase from Aspergillus niger 总被引:2,自引:0,他引:2
Máximo C. Costa-Ferreira M. Duarte J. 《World journal of microbiology & biotechnology》1998,14(3):365-367
An Aspergillus niger isolate produced about 2500nkat xylanase/ml when cultivated in a medium containing 3% xylose. Application of the crude xylanolytic preparation to unbleached eucalyptus kraft pulp resulted in a decreased kappa number and increased brightness. Handsheets made from the xylanase-treated pulp after ECF bleaching retained good structural and mechanical characteristics. 相似文献
4.
Nyéssia Fernanda De Sousa Silva MáRcia Regina Simões Adriana Knob Sandra Schmidt De Moraes Caroline Henn Jose Luis Da ConceiçãO Silva 《Biocatalysis and Biotransformation》2016,34(3):119-127
Xylanase produced from the newly isolated Penicillium crustosum FP 11 and its potential in the prebleaching of kraft pulp were evaluated using a statistical approach. A Plackett–Burman design (PBD) was carried out to select the significant variables of the medium, these being NaNO3, KH2PO4, MgSO4, KCl, Fe2(SO4)3, yeast extract, corn stover, and initial pH, in a liquid culture under static conditions for 6 d at 28?°C. Statistical analysis with a central composite design and response surface methodology showed that 0.15% (w/v) KH2PO4, 2% (w/v) corn stover, and an initial pH of 6.0 provided the best conditions for xylanase production. Furthermore, xylanase from P. crustosum FP 11 was effective in the bleaching of Eucalyptus kraft pulp, with a significant kappa efficiency of 35.04%. Therefore, the newly isolated P. crustosum FP 11 from the Atlantic Forest biome in Brazil showed two advantages: xylanase production with agricultural residue (corn stover) as a carbon source and an improvement in the bleaching of kraft pulp. Environmental pollution could thus be minimized because of a reduction in the use of chlorine as a bleaching agent. 相似文献
5.
AIMS: To optimize the solid-state cultivation conditions for xylanase production using agriresidues and testing the biobleaching efficiency of xylanase on nonwoody plant fibre materials. METHODS AND RESULTS: An extracellular cellulase free xylanase was produced from Bacillus subtilis C 01 using various inexpensive substrates under solid-state cultivation. High level of xylanase production (135 IU gds(-1)) was observed when grown on wheat bran followed by maize powder (50 IU gds(-1)). The maximum xylanase (136 IU gds(-1)) production was occurred in wheat bran-to-moisture ratio of 1 : 1 at 72 h. The xylanase pretreated pulp samples of banana, silk cotton and cotton showed an increased brightness of 19.6, 11.6 and 7.9%, respectively. CONCLUSIONS: The enzyme-aided biobleaching results indicate that the xylanase has potential application in enhancing the brightness of nonwoody plant fibre pulp. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on biobleaching of banana fibres, silk cotton and cotton pulps using xylanase. The biobleaching results of secondary fibres are promising and can be transferred to paper mills, which utilize nonwoody plant fibres as a raw material for paper production. 相似文献
6.
Cellulase-free xylanase from an alkalophilic Bacillussp. was maximally active at pH 10 and 60 °C. Enzyme treatment of ramie fibers removed 40% of its hemicellulose and some chromophoric material which resulted in a brightness increment of 5.2% and boosted the effect of H2O2bleaching. Enzyme-treated ramie fibers were increased by 3.9% in elongation and retained appropriate tenacity. X-ray and scanning electron micrograph studies revealed some changes in fiber structure. 相似文献
7.
A stilbene dye (Direct Yellow 11) and a methine dye, Basazol 46L, recalcitrant to common chemical
bleaches, were treated with horseradish and soybean peroxidases. Both enzymes were effective at chromophore
removal. When compared to laccase in combination with a mediator (ABTS), soybean peroxidase was more
effective at oxidative dye removal, especially for the methine dye. 相似文献
8.
9.
Sinitsyna OA Gusakov AV Okunev ON Serebryany VA Vavilova EA Vinetsky YP Sinitsyn AP 《Biochemistry. Biokhimii?a》2003,68(12):1313-1319
Recombinant endo-beta-1,4-xylanase (Xyl-31rec, 31 kD, pI 8.2-9.3, the tenth family of glycosyl hydrolases) was isolated from the culture liquid of Penicillium canescens (strain with the amplified homologous xylanase gene) by chromatofocusing on Mono P and hydrophobic chromatography on phenyl-Superose. It is shown that the biochemical and kinetic parameters, substrate specificity, stability, and other properties of the recombinant and native enzymes are almost the same. It was found that Xyl-31rec can be used for biobleaching of cellulose, the recombinant P. canescens strains providing a high yield of extracellular Xyl-31rec (up to 800-900 U/ml of culture liquid) and not secreting cellulases. 相似文献
10.
J. Haarhoff C.J. Moes C. Cerff W.J. van Wyk G. Gerischer B.J.H. Janse 《Biotechnology letters》1999,21(5):415-420
The culture supernatant of Thermomyces lanuginosus strains MED 2D and MED 4B1 had high activities of xylanase with low inducible activities of -xylosidase. The crude xylanase was optimally active at 70 °C and at pH 6.0 to 6.5. Subsequently Eucalyptus kraft pulp was treated with MED 2D supernatant at 10 IU per gram pulp resulting in a 10.5% reduction in Kappa number. XECEDED-Refined bleached pulp resulted in handsheets with increased brightness compared to the control (X = xylanase treatment; E = alkaline extraction; C = Cl2 treatment; D = ClO2 treatment). 相似文献