Purification and characterization of a new xylanase with excellent stability from Aspergillus flavus and its application in hydrolyzing pretreated corncobs

2019 ◽  
Vol 154 ◽  
pp. 91-97 ◽  
Author(s):  
Zhou Chen ◽  
Ahmed A. Zaky ◽  
Yangliu Liu ◽  
Yaoyao Chen ◽  
Lu Liu ◽  
...  
2013 ◽  
Vol 10 (3) ◽  
pp. 844-853
Author(s):  
Baghdad Science Journal

Endoglucanase produced from Aspergillus flavus was purified by several steps including precipitation with 25 % ammonium sulphate followed by Ion –exchange chromatography, the obtained specific activity was 377.35 U/ mg protein, with a yield of 51.32 % .This step was followed by gel filtration chromatography (Sepharose -6B), when a value of specific activity was 400 U/ mg protein, with a yield of 48 %. Certain properties of this purified enzyme were investigated, the optimum pH of activity was 7 and the pH of its stability was 4.5, while the temperature stability was 40 °C for 60 min. The enzyme retained 100% of its original activity after incubation at 40 °C for 60 min; the optimum temperature for enzyme activity was 40 °C.


2008 ◽  
Vol 43 (5) ◽  
pp. 547-552 ◽  
Author(s):  
Sangeeta Yadav ◽  
Pramod Kumar Yadav ◽  
Dinesh Yadav ◽  
Kapil Deo Singh Yadav

1963 ◽  
Vol 9 (5) ◽  
pp. 653-664 ◽  
Author(s):  
J. J. Child ◽  
F. J. Simpson ◽  
D. W. S. Westlake

Aspergillus flavus produces an inducible esterase that hydrolyzes the depside, 2-(3′,4′-dihydroxybenzoyloxy)-4,6-dihydroxybenzoic acid. The activity of this enzyme may be followed by measurement of the rate of production of protocatechnic acid, which reacts with alkaline potassium ferricyanide to give a product with an absorption maximum at 540 mμ. Synthesis of the esterase is induced when the organism is grown on rutin, robinin, hyperosid, kaempferol, rhamnetin, myricetin, quercetin, and fisetin, but not when grown on apigenin, galangin, glucose, naringenin, morin, rhamnose, robinetin, or taxifolin. The esterase has been partially purified and separated from the rutinase and quercetinase enzymes. The esterase is most active at pH 4.5. Eighty percent of the activity remained after holding the enzyme for 10 minutes at 60 °C. The enzyme readily attacked the depside linkages in tannic acid but did not hydrolyze common ester substrates such as ethyl butyrate.


2017 ◽  
Vol 32 (1) ◽  
pp. 77 ◽  
Author(s):  
S.O. Kareem ◽  
O.S. Adebayo ◽  
S.A. Balogun ◽  
A.I. Adeogun ◽  
S.B Akinde

1961 ◽  
Vol 7 (6) ◽  
pp. 921-932 ◽  
Author(s):  
G. W. Hay ◽  
D. W. S. Westlake ◽  
F. J. Simpson

Aspergillus flavus produces an adaptive glycosidase (rutinase) that hydrolyzes rutin to quercetin and rutinose. Production of rutinase occurs when the mold is grown on the glycosides rutin, hyperosid, and naringin, and on the aglycones quercetin, kaempferol, rhamnetin, 2,4-dihydroxybenzoic acid, and 3,4-dihydroxyphenylacetic acid, but not when grown on glucose, galactose, rhamnose, or rutinose. Rutinase, after partial purification, is relatively stable when stored at −20 °C, and is most stable and most active at pH 5.6. The enzyme is quite specific, hydrolyzing the 5-glucoside of sakuranetin, the 3-rutinoside and 3-galactoside of quercetin, but not the 3-L-rhamnoside nor any of the common glycosides. The hydrolysis of rutin is carried to completion aided by the insolubility of the aglycone quercetin in water.


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