Highly alkali-stable and cellulase-free xylanases from Fusarium sp. 21 and their application in clarification of orange juice.

Highly alkali-stable and cellulase-free xylanases from Fusarium sp. 21 and their application in clarification of orange juice. Int J Biol Macromol. 2020 Apr 01;: Authors: Li C, Kumar A, Luo X, Shi H, Liu Z, Wu G Abstract Xylanase is a versatile tool in the food, fiber biobleaching and biofuel industries. Here, to discover new enzyme with special properties, we cloned three xylanases (Xyn11A, Xyn11B, and Xyn11C) by mining the genome of the xylanase producing fungus strain Fusarium sp. 21, biochemically characterized these enzyme and explored their potential application in juice processing. Both Xyn11A and Xyn11B had an optimal pH of 6.0 and optimal temperature of 45 °C, and retained >90% of the residual activity at pH range of 5-10.5 for 24 h. Xyn11C displayed the maximum activity at pH 5.0 and 45 °C and outstanding pH stability with a minimal loss of activity in the pH range of 2.0-10.5. These three xylanases displayed a strong specificity towards beechwood and corncob xylan, with no activity for other substrates. Xyn11A showed much a higher activity against corncob xylan, while Xyn11B and Xyn11C presented higher activities against beechwood xylan. Xyn11A catalyzed the hydrolysis of beechwood xylan with a Km of 4.25 ± 0.29 mg·mL-1 and kcat/Km of 30.34 ± 0.65 mL·s-1·mg-1, while the hydrolysis of corncob xylan had Km and kcat/Km values of 14.73 ± 1.43 mg·mL-1and 26.48 ± 0.11 mL·s-1·mg-1, r...
Source: International Journal of Biological Macromolecules - Category: Biochemistry Authors: Tags: Int J Biol Macromol Source Type: research