Optimization of cultural conditions for polygalacturonase production by a newly isolated Aspergillus fumigatus R6 capable of retting kenaf

• Main Authors: Wong, Li Yin, Saad, Wan Zuhainis, Mohamad, Rosfarizan, Md Tahir, Paridah
• Format: Article
• Language: English
• Published: Elsevier 2017
• Online Access: http://psasir.upm.edu.my/id/eprint/62610/1/R6.pdf; http://psasir.upm.edu.my/id/eprint/62610/; https://www.sciencedirect.com/science/article/pii/S0926669016308494#!

Sequential optimization strategy was used to enhance the production of extracellular polygalacturonase by a newly isolated Aspergillus fumigatus R6 using rice bran as a substrate in solid state conditions. Three significant variables influencing the polygalacturonase production were identified as initial moisture level, temperature and incubation time (P < 0.0001). The model established by face-centered central composite design was significant (P < 0.05) with high R2 (0.98). The model validity was verified and the optimum conditions were at an initial moisture level of 49.6%, 33 °C and 129 h of incubation time with the maximum polygalacturonase activity of 565 U/g, resulted in 2.65 fold increase in polygalacturonase activity compare to the unoptimized conditions. Kenaf stem treated with A. fumigatus R6 polygalacturonase enzyme at 72 h produced high strength of kenaf bast fibers (287 MPa) with high Young’s modulus (10404 MPa) and the color is in satisfactory.