A novel low-temperature-active exo-inulinase identified based on Molecular-Activity strategy from Sphingobacterium sp. GN25 isolated from feces of Grus nigricollis

摘要: Abstract A novel glycosyl hydrolase family 32 exo-inulinase (InuAGN25) gene was cloned from Sphingobacterium sp. GN25 isolated feces of Grus nigricollis . InuAGN25 showed the highest identity 54.3% with a putative levanase recorded in GenBank. Molecular-Activity strategy proposed to predict be low-temperature-active before experiments performance. Molecular analyses included progressive sequential, phylogenetic and structural analyses. effectively expressed Escherichia coli The purified recombinant characteristics enzymes: (1) enzyme retained 55.8% maximum activity at 20 °C, 35.8% 10 °C, even 8.2% 0 °C; (2) exhibited 75.8, 30.5 10.8% initial after preincubation for 60 min 45, 50 55 °C, respectively; (3) K m values toward inulin were 2.8, 3.0, 3.2 5.8 mg ml −1 0, 10, 20 40 °C, respectively. Fructose main product Jerusalem artichoke tubers hydrolyzed by room temperature, 10 °C 0 °C. These results suggested worked efficiently made promising production fructose low temperatures.