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Xylanase

About: Xylanase is a research topic. Over the lifetime, 7099 publications have been published within this topic receiving 163793 citations.


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TL;DR: Analysis of enzymes expressed in the transformant cells indicated that neither enzyme was secreted into the culture medium, periplasm nor membrane bound, although xylanase but not β-xylosidase, was secreting into the medium in a B. pumilus culture.
Abstract: The 7.7 Mdal PstI fragment of Bacillus pumilus IPO containing genes for xylan degradation, xylanase, and β-xylosidase was inserted at the PstI site of pBR322 and cloned in E. coli C600. The hybrid plasmid thus formed was named pOXN29. The amount of xylanase and β-xylosidase expressed in E. coli harboring pOXN29 was about 6% and 20% of the activity produced by the donor, B. pumilus. The reverse orientation of the inserted fragment resulted respectively in 5 times and 50 times increases in xylanase and β-xylosidase productivities. Both enzymes expressed in E. coli transformants were shown to be indistinguishable from those of B. pumilus by immunological and chemical criteria. Digestion of pOXN29 with BglII produced two fragments; one was 6.7 Mdal in size and contained the whole pBR322 and the β-xylosidase gene, and the other was 3.7 Mdal and coded for xylanase. Analysis of enzymes expressed in the transformant cells indicated that neither enzyme was secreted into the culture medium, periplasm nor membrane bound, although xylanase but not β-xylosidase, was secreted into the medium in a B. pumilus culture.

74 citations

Journal ArticleDOI
TL;DR: Bacto‐peptone was found to be the most suitable substrate of a number of casein, mycological, and meat peptone preparations for enzyme production and was reported to be active against can cerous cells.
Abstract: A wild strain of Schizophyllum commune (Fr:Fr:) isolated in Bangladesh produced cellulase and xylanase in high yields as well as the exobiopolymer schizophyllan. It was found experimentally that concentrations of 4% Avicel, 3.5% peptone, and 0.5% Ca(NO3)2.4H2O were optimal for growth and product formation. Bacto-peptone was found to be the most suitable substrate of a number of casein, mycological, and meat peptone preparations for enzyme production. Young plate-culture inocula (4 days) were found to be better than comparatively aged fungal cultures (14 days). With the optimized medium, 5 units filter paper (FP) cellulase, 1244 units xylanase, 108 units beta-glucosidase, and 65 units of carboxymethyl (CM) cellulase per mL culture filtrate were obtained in shake flasks. In a laboratory fermentor the respective enzyme activities were 4.5 units FP-cellulase, 1200 units xylanase, 100 units beta-glucosidase, and 60 units CM-cellulase per mL culture filtrate. A biopolymer, reported to be active against cancerous cells, was an additional product in addition to the enzymes. (Refs. 40).

74 citations

Journal ArticleDOI
TL;DR: The catalytic domain of a xylanase from the anaerobic fungus Neocallimastix patriciarum was made more alkalophilic through directed evolution using error-prone PCR to suggest that the composite mutant xylanases is a promising and suitable candidate for paper pulp bio-bleaching.
Abstract: The catalytic domain of a xylanase from the anaerobic fungus Neocallimastix patriciarum was made more alkalophilic through directed evolution using error-prone PCR. Transformants expressing the alk...

74 citations

Journal ArticleDOI
TL;DR: The results demonstrated that the individual cellulases have profoundly different modes of action in modifying pulp carbohydrates, and the exploitation of cellulases for fibre treatments requires careful optimization of both enzyme composition and dosage.
Abstract: Four purified cellulases, a xylanase and mannanase from Trichoderma reesei were used to treat never-dried bleached pine kraft pulp prior to refining, and the effects on pulp properties were evaluated. The enzymatic treatments hydrolysed up to 0.8% of pulp dry weight. The results demonstrated that the individual cellulases have profoundly different modes of action in modifying pulp carbohydrates. This is especially clear when comparing their effects at the same level of hydrolysis. Pretreatment with cellobiohydrolases I (CBH I) and II (CBH II) had virtually no effect on the development of pulp properties during refining, except for a slight decrease in strength properties. On the contrary, endoglucanase I (EG I) and endoglucanase II (EG II) improved the beatability of the pulp as measured by Schopper--Riegler value, sheet density and Gurley air resistance. Of the endoglucanases, EG II was most effective in improving the beating response. The combinations of CBH I with EG I and EG II had similar effects on the pulp properties as the endoglucanases alone, although the amount of hydrolysed cellulose was increased. Pretreatments with xylanase or mannanase did not appear to modify the pulp properties. The same enzyme treatments which improved the beatability, however, slightly impaired the pulp strength, especially tear index at the enzyme dosages used. When compared at a given level of cellulose hydrolysis, the negative effect of EG II on strength properties was more pronounced compared with EG I. Thus, the exploitation of cellulases for fibre treatments requires careful optimization of both enzyme composition and dosage. Since the endoglucanases had no positive effect on the development of tensile strength, it is suggested that the explanation for the increased beating response is increased fibre breakage and formation of fines, rather than improved flexibilization.

74 citations

Journal ArticleDOI
TL;DR: Hemicellulases and an endoglucanase from seven different fungi were assessed for their potential to solubilze mannan and xylan from softwood sulfite dissolving pulps and a xylanase from Thermomyces lanuginosus and a mannanase from Sclerotium rolfsii acted synergistically on the pulpsolubilizing 50% more mannanand 11% more xylan than did the individual enzymes.
Abstract: Hemicellulases and an endoglucanase from seven different fungi were assessed for their potential to solubilze mannan and xylan from softwood sulfite dissolving pulps. A xylanase from Thermomyces lanuginosus and a mannanase from Sclerotium rolfsii acted synergistically on the pulp solubilizing 50% more mannan and 11% more xylan than did the individual enzymes. The addition of an endoglucanase further increased both the amount of xylan and mannan that was solubilized from the pulp.

74 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023199
2022463
2021254
2020289
2019278
2018303