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Thermal stabilization by polyols of β‐xylanase from Bacillus amyloliquefaciens
Author(s) -
Breccia Javier D.,
Morán Ana C.,
Castro Guillermo R.,
Siñeriz Faustino
Publication year - 1998
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/(sici)1097-4660(199803)71:3<241::aid-jctb810>3.0.co;2-g
Subject(s) - sorbitol , bacillus amyloliquefaciens , xylanase , chemistry , circular dichroism , polyol , incubation , nuclear chemistry , enzyme , chromatography , food science , biochemistry , organic chemistry , fermentation , polyurethane
Purified endo‐β‐1,4‐xylanase of Bacillus amyloliquefaciens MIR 32 retained 100% of its activity after 4 days of incubation at 50°C. Sorbitol (400 mg cm −3 ) produced a 63‐fold increase in the half‐life of the enzyme at 65°C, which was only 29 min at this temperature in the absence of the polyol. This thermal stabilizing activity increased exponentially in respect to sorbitol concentration in the range 250–400 mg cm −3 and was dependent on the pH, showing a maximum at pH values between 5·25 and 8·0. The circular dichroism (CD) thermal scanning profile (50°C h −1 ) at 224 nm showed that changes in the secondary structure of xylanase started at 65°C, while in the presence of sorbitol (400 mg cm −3 ) these modifications started at 80°C. This study indicated that sorbitol might be a valuable stabilizer for the use of β‐xylanase from B . amyloliquefaciens at high temperatures. © 1998 SCI