High-level expression of a thermophilic and acidophilic β-mannanase from Aspergillus kawachii IFO 4308 with significant potential in mannooligosaccharide preparation. (January 2020)

• Record Type: Journal Article
• Authors: Liu, Zhemin; Ning, Chen; Yuan, Mingxue; Yang, Suxiao; Wei, Xinyi; Xiao, Mengshi; Fu, Xiaodan; Zhu, Changliang; Mou, Haijin
• Is Part Of: Bioresource technology. Volume 295(2020)
• Publication Date: 2020-01
• Subjects: Extreme β-mannanase -- Pichia pastoris -- Hydrolysis products analysis -- Degradation patterns -- Mannooligosaccharide; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2019.122257
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: A thermophilic and acidophilic β-mannanase was highly expressed in P. pastoris . ManAK could efficiently degrade mannans (LBG, KG, and GG) in extreme conditions. The catalytic pocket of ManAK could only accommodate one galactopyranosyl residue. ManAK is a good candidate with great potential in MOS preparation. Abstract: An engineered thermophilic and acidophilic β-mannanase (ManAK) from Aspergillus kawachii IFO 4308 was highly expressed in Pichia pastoris . Through high cell density fermentation, the maximum yield reached 11, 600 U/mL and 15.5 g/L, which is higher than most extreme β-mannanases. The recombinant ManAK was thermostable with a temperature optimum of 80 °C, and acid tolerant with a pH optimum of 2.0. ManAK could efficiently degrade locust bean gum, konjac gum, and guar gum into small molecular mannooligosaccharide (<2000 Da), even at high initial substrate concentration (10%), and displayed different Mw distributions in their end products. Docking analysis demonstrated that the catalytic pocket of ManAK could only accommodate a galactopyranosyl residue in subsite −1, which might be responsible for the distinct hydrolysis product compositions from locust bean gum and guar gum. These superior properties of ManAK strongly facilitate mannooligosaccharide preparation and application in food and feed area.