Characterization of a Novel Thermophilic Mannanase and Synergistic Hydrolysis of Galactomannan Combined with Swollenin

Catalysts

Haiqiang Lu¹  Wei Chen¹  Xiangchen Meng²  Xinxi Gu² 

[1] College of Food Science and Technology, Hebei Agricultural University, Baoding 071001, China;Key Laboratory of Dairy Science, Ministry of Education, Northeast Agricultural University, Harbin 150030, China;

关键词: mannanase;    swollenin;    synergistic;    galactomannan;    hydrolysis;   

DOI  :  10.3390/catal11020254

来源: DOAJ

【 摘 要 】

Aspergillus fumigatus HBFH5 is a thermophilic fungus which can efficiently degrade lignocellulose and which produces a variety of glycoside hydrolase. In the present study, a novel β-mannanase gene (AfMan5A) was expressed in Pichia pastoris and characterized. AfMan5A is composed of 373 amino acids residues, and has a calculated molecular weight of 40 kDa. It has been observed that the amino acid sequence of AfMan5A showed 74.4% homology with the ManBK from Aspergillus niger. In addition, the recombined AfMan5A exhibited optimal hydrolytic activity at 60 °C and pH 6.0. It had no activity loss after incubation for 1h at 60 °C, while 65% of the initial activity was observed after 1 h at 70 °C. Additionally, it maintained about 80% of its activity in the pH range from 3.0 to 9.0. When carob bean gum was used as the substrate, the Km and Vmax values of AfMan5A were 0.21 ± 0.05 mg·mL⁻¹ and 15.22 ± 0.33 U mg⁻¹·min⁻¹, respectively. AfMan5A and AfSwol showed a strong synergistic interaction on galactomannan degradation, increasing the reduction of the sugars by up to 31%. Therefore, these findings contribute to new strategies for improving the hydrolysis of galactomannan using the enzyme cocktail.

【 授权许可】

Unknown