Modifying solubility of polymeric xylan extracted from Eucalyptus grandis and sugarcane bagasse by suitable side chain removing enzymes.

α -l- Arabinofuranosidase (AbfB) and novel α- d -glucuronidase (Agu1B) enzymes were applied for selective hydrolysis of beechwood ( Fagus sylvatica ) xylan (Sigma–Aldrich) as well as xylans extracted from Eucalyptus grandis and sugarcane ( Saccharum officinarum L.) bagasse, leading to precipitation of these carbohydrate biopolymers. Hemicellulose extraction was performed with two mild-alkali methods, Höije and Pinto. Precipitation occurred after removal of 67, 40 and 16% 4- O -methyl- d -glucuronic acid (MeGlcA) present in polymeric xylans from beechwood, E. grandis (Pinto) and E. grandis (Höije), respectively. Precipitation was maximized at Agu1B levels of 3.79–7.53 mg/g substrate and hemicellulose concentrations of 4.5–5.0% (w/v). Polymeric xylan from sugarcane bagasse precipitated after removal of 48 and 22% of arabinose and MeGlcA, respectively, at optimal AbfB and Agu1B dosages of 9.0 U/g and 6.4 mg/g, respectively. Both the purity of polymeric xylans and structure thereof had a critical impact on the propensity for precipitation, and morphology of the resulting precipitate. Nano-to micro-meter precipitates were produced, with potential for carbohydrate nanotechnology applications. [ABSTRACT FROM AUTHOR]