ARS | Publication request: OPTIMIZATION OF APPLICATIONS OF DEXTRANASES IN SUGARCANE FACTORIES

Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: April 22, 2005
Publication Date: June 1, 2005
Citation: Eggleston, G., Monge, A., Stewart, D., Montes, B. 2005. Optimization of applications of dextranases in sugarcane factories [abstract]. Sugar Journal. 68(1):33.

Technical Abstract: The application of commercial dextranases (1, 6-alpha-glucan hydrolases, EC 3.2.1.11) to breakdown dextran (alpha-(1'6)-alpha-D-glucan) in U.S. sugar manufacture is still not optimized, partly because of misinformation about where to add the enzyme and which enzyme to use. Furthermore, there was no uniform method to measure the activity of commercial dextranases by vendors, which meant that direct comparison of activities was not possible. Most commercial dextranases in the U.S. are from Chaetomium gracile or erraticum, and studies on the industrial optimization of dextranases were conducted at two Louisiana factories in 2004. Several factories are now successfully using the simple, titration method (Eggleston, 2004) for the determination of the relative activity of dextranases. Several factories have also chosen to use "concentrated" dextranase rather than traditional "non-concentrated" dextranases. An approximate 14 to 20-fold difference in activity now exists between the two concentration forms. As dextranase applications to syrup are relatively uneconomical, only juice applications were studied. For dextranase application, one factory had installed a 5 min retention time (Rt) tank adjacent with the cush-cush tank, and the other factory used a 17 min Rt incubation tank. Dextran removal across the tanks was measured using both monoclonal antibody and Haze (alcohol precipitation) methods. Higher ppm levels of dextranase were required for application to juice in the factory than to juice studied in the laboratory. The greater the amount of dextran the easier it is to breakdown by dextranase, because of increased substrate/enzyme ratios. Pre-dilution and stability of the "concentrated" dextranase at the factory into a working solution, to improve juice dextran/dextranase contact is also reported. The effect of increasing the temperature from ~90 degrees F to ~120 degrees F is discussed. Dextranase application did not always alleviate all processing problems in factory boiling stations, because lower MW dextrans and other Leuconostoc deterioration products still existed.