Improvement of xylanase production by Cochliobolus sativus in solid state fermentation

Bakri, Yasser; Jawhar, M.; Arabi, M. I. E.

doi:10.1590/s1517-83822008000300036

Cited by 21 publications

(23 citation statements)

References 12 publications

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“…This might be due to the fact that alkaline pH has inhibitory effect on the growth of the fungus and enzyme production. In addition, cultivation of fungi at an unfavorable pH value may result in reduced enzyme production by reducing accessibility of the substrate (Bakri et al, 2008). Garcia-Kirchner et al (2005) also optimized pH 5.5 for the production of β-glucosidase from A. niger.…”

Section: Resultsmentioning

confidence: 99%

Metabolic engineering and thermodynamic characterization of an extracellular -glucosidase produced by Aspergillus niger

Zahoor¹,

Javed²,

Aftab³

et al. 2011

Afr. J. Biotechnol.

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The production of an extracellular β-glucosidase by Aspergillus niger NRRL 599 was optimized using submerged fermentation technique. Effect of different media, different carbon sources, initial pH of the fermentation medium, temperature, incubation period and inoculum size on the production of β-glucosidase enzyme was investigated. A. niger NRRL 599 produced maximum extracellular β-glucosidase (4.48 U/mg) in Eggins and Pugh medium with 1% wheat bran (w/v) at pH 5.5 inoculated with 4% conidial suspension after 96 h of incubation at 30°C. Purified β-glucosidase gave K m and V max values of 3.11 mM and 20.83 U/mg respectively for pNPG hydrolysis. The enzyme was optimally active at pH 4.8 and at temperature of 60°C. Thermodynamic parameters, E a , ∆H and ∆S were found to be 52.17 KJ/mol, 49.90 J/mol.K and -71.69 KJ/mol, respectively. The pKa 1 and pKa 2 of ionizable groups of active site residues involved in V max were calculated to be 4.1 and 6.0 respectively.

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Section: Resultsmentioning

confidence: 99%

Metabolic engineering and thermodynamic characterization of an extracellular -glucosidase produced by Aspergillus niger

Zahoor¹,

Javed²,

Aftab³

et al. 2011

Afr. J. Biotechnol.

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“…The enzyme was cellulase-free as the crude extract was devoid of cellulase activity. Lignocellulosic materials have been used earlier by various researchers for production of xylanase but with lower activity (3,9,12).…”

Section: Enzyme Activitymentioning

confidence: 99%

One-step purification and characterization of cellulase-free xylanase produced by alkalophilic Bacillus subtilis ash

Sanghi¹,

Garg²,

Gupta³

et al. 2010

Braz. J. Microbiol.

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The present study describes the one-step purification and characterization of an extracellular cellulase-free xylanase from a newly isolated alkalophilic and moderately thermophilic strain of Bacillus subtilis ASH.Xylanase was purified to homogeneity by 10.5-fold with ~43% recovery using ion-exchange chromatography through CM-Sephadex C-50. The purified enzyme revealed a single band on SDS-PAGE gel with a molecular mass of 23 kDa. It showed an optimum pH at 7.0 and was stable over the pH range 6.0-9.0. The optimum temperature for enzyme activity was 55 °C. The purified xylanase did not lose any activity up to 45 ºC, however, it retained 80% and 51% of its activity after pre-incubation at 55 ºC and 60 ºC, respectively. The enzyme obeyed Michaelis-Menton kinetics towards birch wood xylan with apparent K m 3.33 mg/ml and V max 100 IU/ml. The enzyme was strongly inhibited by Hg 2+ and Cu 2+ while enhanced by Co 2+ and Mn 2+. The purified enzyme could be stored at 4 ºC for six weeks without any loss of catalytic activity. The faster and economical purification of the cellulase-free xylanase from B. subtilis ASH by onestep procedure together with its appreciable stability at high temperature and alkaline pH makes it potentially effective for industrial applications.

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“…Xylanase cultivation medium which contained Mg 2+ ions only showed 73% activity as compared to that in Czapek-Dox medium which contained both Fe 2+ and Mg 2+ ions. Further, there are reports [13][14][15] which suggest that organic source of nitrogen support the maximum enzyme production. Keeping this in view, the Czapek-Dox medium was modified with respect to trace metal ions and nitrogen source.…”

Section: Optimization Of Culture Conditionsmentioning

confidence: 99%

Isolation, Screening and Optimized Production of Extracellular Xylanase under Submerged Condition from Aspergillus Flavus Mtcc 9390

Bhushan¹,

Pal²,

Jain³

2011

Enzyme Engg

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In order to isolate xylanolytic microbial strains, screening and isolation was done using agricultural waste and decaying biomass. The enzyme super-secreter Aspergillus flavus MTCC 9390 was selected for optimized production of xylanase. Various process variables were optimized using conventional 'one-variable-at-a-time' approach which involves varying a single independent variable and maintaining others at a constant level. All culture conditional variables had profound influence on enzyme production and 15-30% increase was brought by nitrogen source only. A synergistic five-fold increase in xylanase production was achieved when an inoculums size of 2 x 10 6 spores/ mL was incubated in modified Czapek Dox-A for 6 days at pH 6.0 and temperature 45ºC under static conditions in submerged fermentation.

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Improvement of xylanase production by Cochliobolus sativus in solid state fermentation

Cited by 21 publications

References 12 publications

Metabolic engineering and thermodynamic characterization of an extracellular -glucosidase produced by Aspergillus niger

Metabolic engineering and thermodynamic characterization of an extracellular -glucosidase produced by Aspergillus niger

One-step purification and characterization of cellulase-free xylanase produced by alkalophilic Bacillus subtilis ash

Isolation, Screening and Optimized Production of Extracellular Xylanase under Submerged Condition from Aspergillus Flavus Mtcc 9390

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