Nonspecific Activity of Bacillus acidopullulyticus Pullulanase on Debranching of Guar Galactomannan

Mysore, S. Shobha and Tharanathan, R. N. (2008) Nonspecific Activity of Bacillus acidopullulyticus Pullulanase on Debranching of Guar Galactomannan. Journal of Agricultural and Food Chemistry, 56. pp. 10858-10864.

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Abstract

Pullulanase (EC 3.2.1.41) from Bacillus acidopullulyticus could preferentially remove galactose residues from guar galactomannan (GG), a heteropolymer consisting of polymannan backbone with alternating galactose as single-residue side-chain stubs. The enzyme showed maximum activity at pH 4.5 and 45 °C and exhibited Michaelis-Menten kinetics with a Km and Vmax of 6.0 mg mL-1 and 1820 nmol min-1 mg-1, respectively. The native and modified GG had a viscosity of 4800 and 3800 cps, respectively. The molecular mass of the enzyme-treated GG varied between 152 ( 0.5 kDa, and its GLC analysis revealed a significant change in galactose-mannose content of 1:3.8, respectively, similar to that of locust bean gum (LBG). FTIR and solid-state CP-MASS 13C NMR analyses indicated subtle changes in the conformation of modified GG because of the removal of galactose residues. Gel-strength measurements with κ-carrageenan showed an improvement in the gelling behavior, similar to that shown by LBG. Debranching of GG by pullulanase is an alternative and inexpensive route to produce modified GG with enhanced functional properties, as a cost-effective replacement for LBG.

Item Type:	Article
Uncontrolled Keywords:	Guar galactomannan; pullulanase; debranching; locust bean gum; K-carrageenan
Subjects:	600 Technology > 08 Food technology > 22 Legumes-Pulses 500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 28 Polysaccharide Chemistry
Divisions:	Dept. of Biochemistry
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	05 Jan 2009 09:52
Last Modified:	28 Dec 2011 10:07
URI:	http://ir.cftri.res.in/id/eprint/8873

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