Characterization of Thermotoga thermarum DSM 5069 α-Glucuronidase and Synergistic Degradation of Xylan

Abstract

* α-Glucuronidases are capable of breaking down the α-1,2-glycosidic bonds of 4-O-methyl-D-glucuronic acid residues. As an accessory enzyme, α-glucuronidase plays a vital role in xylan degradation. The recombinant α-glucuronidase from Thermotoga thermarum DSM 5069 was heterologously expressed in the Escherichia coli system, purified, and characterized. The purified enzyme exhibited optimal activity toward aldouronic acids at pH 6.5 and 80 °C. It was fairly thermostable and maintained 98% residual activity after incubation at 65 °C for 2.0 h. The kinetic parameters Km, Vmax, and kcat were 3.02 ± 0.16 mM, 88 ± 2 µmol min -1 mg

Invited Review: Biodiversity of Plant Polysaccharide-Degrading Bacteria in Mangrove Ecosystem

“…β-D-xylosidase hydrolyzes xylobiose or xylo-oligosaccharides at the non-reducing end, producing monosaccharide, D-xylose sugar (Biely et al 2016). In addition, α-L-arabinofuranosidase (EC 3.2.1.55), acetylxylan esterase (EC 3.1.1.73), α-galactosidase (EC 3.2.1.22), α-glucuronidase (EC 3.2.1.139), feruloyl esterase (EC 3.1.1.72), β-mannosidase (EC 3.2.1.25) and mannan endo-1,4-β-mannosidase (EC 3.2.1.78) involve in the hydrolysis because of the heterogeneity and complexity of xylan (Shallom & Shoham 2003;Liao et al 2016;Wang et al 2016;Contesini et al 2017). Endo-1,4β-D-mannanase (EC 3.2.1.78) catalyzes hydrolysis of β-D-1,4-mannopyranosyl linkages consisting of the main chain of mannans, galactomannans, glucomannans and galactoglucomannan (Dekker & Richards 1976).…”