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ARPN Journal of Science and Technology >> Volume 7, Issue 1, January 2017

ARPN Journal of Science and Technology

Isolation, Purification and Characterization of a Xylanase from Aspergillus Flavus for Possible use in Paper Industry

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Author M.A.Milala, A.J.Nok, H.M. Inuwa, S. Ibrahim
ISSN 2225-7217
On Pages 1090-1104
Volume No. 3
Issue No. 11
Issue Date December 01, 2013
Publishing Date December 01, 2013
Keywords M.A.Milala, A.J.Nok, H.M. Inuwa, S. Ibrahim


Aspergillus flavus was grown in basal mineral salt medium (MSM) with pretreated composite sawdust as the only carbon source under submerged fermentation conditions. The fermentation lasted for 216 hours (9 days) in an incubator shaker 150rpm at 37oC. Maximum xylanase production was at 72 hour incubation, with specific activity of 1.12x10-3umol/min/mg protein. Crude sample was precipitated with 20-90% ammonium sulphate. The highest specific activity was at 70% fractionation. The purification of xylanase from Aspergillus flavus included ammonium sulphate precipitation, Gel molecular exclusion (G-75) and DEAE-Cellulose (DE-52) chromatography. The specific activity increased from 1.47x10-3umol/min/mg to 5.31x10-2umol/min/mg with a purification fold of 36.12 and yield of 6.83%. Aspergillus flavus had optimum activity at pH5 and temperature of 50O C. The xylanase also had activation energy of 7.73kJ/mol, KM of 0.625mg/ml and Vmax of 0.00429µmol/min. The purified xylanase was homogenous by SDS-polyacrylamide gel electrophoresis with molecular weight estimated to be 28 KDa. The partially purified enzyme was strongly inhibited by 50µ? of Hg2+ and Pb2+, while the same concentration of Cu2+, Mg2+ and Zn2+ has slight inhibition. Ca2+ and Mn2+ had no effects, but Fe2+ had strong stimulatory effects and Co2+ had stimulatory effects. From the study, the partially purified xylanase from Aspergillus flavus may not be good for applications in industries, where high temperature and alkaline pH is required

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