Purification and characterization of tannin acyl hydrolase from Aspergillus niger MTCC 2425

Abstract

The present investigation was carried out for increasing the yield of tannase of Aspergillus niger and the physico-chemical characterization of this enzyme. the extraction of enzyme protein. However, extraction of fungal pigments and proteins was observed to have high pH dependence, and maximum enzyme extraction was obtained at pH 5.5. The two-step purification protocol gave 51-fold purified enzyme with a yield of 20%. The total tannase activity was made up of nearly equal activity of esterase and depsidase. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of purified tannase protein indicated it to be made up of two polypeptides of molecular weight 102 and 83 kDa. Based on the Michaelis-Menten constant (Km) of tannase for three substrates tested, tannic acid was the best substrate with Km of 2.8 x 10(-4) M, followed by methyl gallate and propyl gallate. The inhibition was maximum for CaCl2 (58%) whereas EDTA had no modulatory effect on tannase activity. The inhibitor binding constant (KI) of CaCl2 was 5.9 x 10(-4) M Homogenization and detergent pretreatments did not have any remarkable effect on and the inhibition was of noncompetitive type.

Biodegradation of gallotannins and ellagitannins

“…The inhibition on tannase activity was maximized for CaCl 2 (58%, w/v) whereas EDTA had no modulatory effect on it. The inhibitor binding constant (K I ) of CaCl 2 was 5.9 × 10 -4 M and the inhibition was of noncompetitive type (BHARDWAJ et al 2003). A tannase-producing bacterial strain KBR 6 has been isolated from lateritic soil and identified as Bacillus licheniformis.…”

Efficient degradation of tannic acid by black Aspergillus species

“…Though A. niger is known to grow on high concentrations of tannic acid, it was the non-black A. oryzae that was for a long time known for its tannase production (Hatomoto et al 1996). Recently, however, the black A. niger and its close relative A. foetidus have been used in tannase studies as well (Aguilar et al 2001, Bhardwaj, Singh & Bhat 2003, Ramirez-Coronel et al 2003, Mukherjee & Banerjee 2004.…”

Effect of fermentation system on the production and properties of tannase of Aspergillus niger van Tieghem MTCC 2425

“…Processing: The concentration, dialysis, lyophilization and reconstitution of the crude extract were done by the protocol of Bhardwaj et al (2003). Tannase was assayed by the spectrophotometric method of Sharma et al (2000).…”

“…A fungus, Aspergillus niger van Tieghem, having high tannin-tolerating capacity and tannin-degrading activity was isolated from faecal samples of hill cattle fed largely on oak leaves (Bhat et al, 1996(Bhat et al, , 1997 and used for upgradation of a tanniferous forage, with partial success (Rakesh et al, 2000). The tannindegrading enzyme of this fungal strain has been partially purified and characterized (Bhardwaj et al, 2003;Sharma et al, 1999).…”

“…In earlier studies on A. niger van Tieghem intracellular tannase (Bhardwaj et al, 2003;Sharma et al, 1999), the enzyme was produced by submerged fermentation (SmF). Intracellular tannase is the main form of the enzyme produced by various fungal strains during SmF.…”