Kinetics of xylanase treatment of hardwood pulp

Valchev, Ivo; Yotova, Lyubov; Valcheva, Eva

doi:10.1016/s0960-8524(98)00020-0

Cited by 13 publications

(11 citation statements)

References 3 publications

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“…The study showed that with lower lignin content in the lignocellulose, the optimum pH required for the hydrolysis was also slightly reduced to lower pH values (Divya Nair et al, 2011). In a previous enzymatic study performed on kraft pulp (where the lignin content is normally < 10%), the hydrolysis was performed at a much lower pH of 3.5 (Valchev et al, 1998). Table 3 demonstrated that the optimal pH range for enzymatic hydrolysis of complex and insoluble lignocellulosic substrates differs with the type of substrates.…”

Section: Fig 3 Effect Of Different Ph On Hemicellulose Hydrolysis Ofmentioning

confidence: 93%

Enzymatic Hydrolysis of Pretreated Kenaf using a Recombinant Xylanase: Effects of Reaction Conditions for Optimum Hemicellulose Hydrolysis

Azelee¹,

Jahim²,

Ismail³

et al. 2016

American Journal of Agricultural and Biological Sciences

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An efficient hemicellulose hydrolysis has now become a crucial step for xylooligosaccharides production for food additives and nutraceuticals industries. In this study, xylanase hydrolysis of pretreated hemicellulosic kenaf (Hibiscus cannabinus) for substantial hemicellulose hydrolysis was demonstrated. Experiments were performed primarily to investigate the effect of several critical reaction conditions towards the enzymatic hydrolysis of the pre-treated kenaf. The effects of various ranges of reaction conditions (substrate loading, xylanase loading, pH, temperature and time) were systematically and thoroughly studied. The study of hemicellulosic kenaf conversion using single enzyme was proven to effectively yield up to 59% of conversion after 48 h incubation using 3% (w/v) of substrate loading and 400 U of xylanase loading at 50°C in pH 4.0 buffer systems. The use of a single xylanase on the pre-treated kenaf was a key parameter in understanding the action of the main hemicellulose degrading enzyme towards hydrolysing the hemicellulose backbone of the pre-treated kenaf. Enzyme feeding strategy was also conducted and the results revealed that a batch feeding strategy of 400 U xylanase loading yielded the highest hemicellulose hydrolysis compared to the other fed batch enzyme feeding strategy. It was concluded that each reaction conditions and enzyme feeding strategy gave a significant impact towards the enzymatic hydrolysis and the use of optimum reaction conditions resulted in a high product yield at the end of the reaction. With the discovery of the importance of each reaction conditions involved in a hydrolysis, this study highlights the need for a comprehensive investigation on the reaction conditions using a mixture of enzymes towards achieving a complete hydrolysis with a higher product yield.

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Section: Fig 3 Effect Of Different Ph On Hemicellulose Hydrolysis Ofmentioning

confidence: 93%

Enzymatic Hydrolysis of Pretreated Kenaf using a Recombinant Xylanase: Effects of Reaction Conditions for Optimum Hemicellulose Hydrolysis

Azelee¹,

Jahim²,

Ismail³

et al. 2016

American Journal of Agricultural and Biological Sciences

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“…Chemical bleaching by alkaline extraction processes was accomplished using the pulps obtained after different treatment times with xylanase (XE) and pulps without any previous enzymatic treatment (E). For this purpose, 3 g of dry pulp were treated with 150 cm 3 1 mol m −3 sodium hydroxide (NaOH) at 65 • C for 1 h under magnetic stirring, filtrated, and washed with another 150 cm 3 of distilled water at 65 • C until the suspension reached the pH 6.0.…”

Section: Methodsmentioning

confidence: 99%

“…Some problems related to the use of chlorine containing bleaching agents are associated with corrosion of storage tanks, formation of toxic and/or mutagenic organic chlorinated compounds, and the increase of chloride and absorbable organic halogen (AOX) levels in bleaching plant effluents [2]. An alternative method applicable in bleaching processes is the enzymatic treatment [3,4].…”

Section: Introductionmentioning

confidence: 99%

Ethanol/water pulp enzymatic pretreatment: Chemical and FTIR-PCA analyses

Ruzene¹,

Gonçalves²

2007

Chemical Papers

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Pulps obtained from ethanol/water cooking of sugarcane bagasse were treated at different times using xylanase enzyme obtained from Thermomyces lanuginosus IOC-4145 or commercially (Cartazyme HS, Sandoz Products Ltd.). The enzyme dosage was 18 IU per g of dry pulp and the time varied from 4 h to 12 h. When xylanase from T. lanuginosus was used, the kappa number and viscosity improved independently of the processing time used (4 h, 8 h, and 12 h). After chemical evaluation, the obtained pulps were classified using Fourier Transformed Infra-Red Spectroscopy and Principal Component Analysis. The results showed that the first three principal components explained more than 90 % of the total variance of the pulp spectra.

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“…Xylanase (1,4‐β‐D‐xylan xylanohydrolase; EC 3.2.1.8) obtained from microorganisms has attracted a great deal of attention in the last decade because of the biotechnological potential of xylanase. Xylanases are produced on an industrial scale for use as bleaching agents in the paper and pulp bleaching industry (Wong and others 1996; Valchev and others 1998). Xylanases are also used as food additives in poultry products (Cowieson and others 2005) and in flour for improving dough handling (Selinheimo and others 2006) and quality of baked products (Jiang and others 2005), as well as for clarification of juices and wines (Hang and Woodams 1997; Gil and Valles 2001).…”

Section: Introductionmentioning

confidence: 99%

Application of Statistical Experimental Design to Optimize Culture Requirements of Aspergillus sp. Zh‐26 Producing Xylanase for Degradation of Arabinoxylans in Mashing

Li¹,

Cui²,

Xu³

et al. 2007

Journal of Food Science

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The objective of this study was to isolate and characterize a strain of Aspergillus capable of producing xylanase. According to the morphology and comparison of ITS (Internal Transcribed Spacer) rDNA gene sequence, the strain Aspergillus sp. ZH-26 was identified as a strain of Aspergillus awamori. Statistically based experimental designs were applied for the optimization of xylanase production from A. awamori ZH-26. The considered medium components included 17 components as follows: yeast extract, tryptone, urea, NH(4)Cl, (NH(4))(2)SO(4), NaNO(3), KH(2)PO(4), K(2)HPO(4), NH(4)NO(3), MgSO(4), CaCl(2), CuSO(4), ZnCl(2), FeSO(4), MnSO(4), vitamin B(1), and EDTA. Yeast extract, tryptone, (NH(4))(2)SO(4), KH(2)PO(4), and CaCl(2) were identified to have significant effects on xylanase production using the Plackett-Burman experimental design. These 5 major components were subsequently optimized using the Box-Behnken experimental design. By response surface methodology and canonical analysis, the optimal concentrations for higher production of xylanase were yeast extract 5.95 g/L, tryptone 6.79 g/L, (NH(4))(2)SO(4) 13.37 g/L, KH(2)PO(4) 1.14 g/L, CaCl(2) 0.81 g/L. Under optimal conditions, the xylanase activity from A. awamori ZH-26 reached 47.3 U/mL. A small-scale mashing was carried out to evaluate the performance of the xylanase on degradation of arabinoxylans in mashing. Results showed that polymeric arabinoxylan content and wort viscosity in mashing with grist containing wheat malt sharply decreased to the basal level (from 470 to 185 mg/L) with the addition of xylanase.

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Kinetics of xylanase treatment of hardwood pulp

Cited by 13 publications

References 3 publications

Enzymatic Hydrolysis of Pretreated Kenaf using a Recombinant Xylanase: Effects of Reaction Conditions for Optimum Hemicellulose Hydrolysis

Enzymatic Hydrolysis of Pretreated Kenaf using a Recombinant Xylanase: Effects of Reaction Conditions for Optimum Hemicellulose Hydrolysis

Ethanol/water pulp enzymatic pretreatment: Chemical and FTIR-PCA analyses

Application of Statistical Experimental Design to Optimize Culture Requirements of Aspergillus sp. Zh‐26 Producing Xylanase for Degradation of Arabinoxylans in Mashing

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