Purification and physicochemical characterisation of Aspergillus niger USM F4 β-mannanase

Abstract

Aims: This present study focused on purification of fungal β-mannanase produced by Aspergillus niger USM F4 and also physicochemical characterisation of the purified enzyme. Methodology and results: The purified β-mannanase with a molecular mass of ~47.4 kDa was demonstrated on SDS-PAGE gel. The enzyme signified a purification degree of 4-fold, with final specific activity of 196.42 U/mg. It reached an optimum catalytic activity at pH 4.0 and 60 °C. The thermal stability of the enzyme was up to 70 °C and maintained the 50% activity after 30 min at 80 °C. Meanwhile, the pH stability was in the range of pH 3.0 -9.0 and a 30 min half-life at pH 10.0. All chemical substances manifested an inhibitory effect on purified β-mannanase, with SDS (28.16 ± 0.05% residual activity) as the strongest inhibitor, followed by cupric ion (Cu 2+ ) (49.51 ± 0.09% residual activity). As a whole, the enzyme displayed a substrate specificity in the order of locust bean gum (LBG) > carboxymethylcellulose > soluble starch > xylan from oat spelt > α-cellulose. Its preference for LBG has generated the Km and Vmax values of 0.20 mg/mL and 9.82 U/mL, respectively. Conclusion, significance and impact of study: The outcomes of our study offer potential for use at industrial scales, particularly in the oligosaccharides production that involve acid-related activity, wide-ranging temperature and pH stability.

The Purification and Biochemical Characterization of a Weissella cibaria F1 Derived β-Mannanase for Its Use in the Preparation of Konjac Oligo-Glucomannan with Immunomodulatory Properties

“…casei HDS-01 [9], Streptomyces sp. NRRL B-24484 [33], A. niger USM F4 [34], Paenibacillus thiaminolyticus [35], and Psychrobacter pulmonis [36]. The other surfactants and inhibitors, such as EDTA, TritionX-100, DTT, and CTAB, inhibited W. cibaria F1 mannanase activity in the present study, similar to previous reports [4,34,35].…”