title: Modifying solubility of polymeric xylan extracted from Eucalyptus grandis and sugarcane bagasse by suitable side chain removing enzymes.
abstract: 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 3.79-7.53mg/gsubstrate 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 9.0U/g and 6.4mg/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.
authors.affiliation: Department of Process Engineering, Stellenbosch University, Stellenbosch, South Africa.
authors.forename: Katiana R
authors.initials: KR
authors.lastname: Gomes
authors.affiliation: Department of Process Engineering, Stellenbosch University, Stellenbosch, South Africa.
authors.forename: Annie F A
authors.initials: AF
authors.lastname: Chimphango
authors.affiliation: Department of Process Engineering, Stellenbosch University, Stellenbosch, South Africa. Electronic address: jgorgens@sun.ac.za.
authors.forename: Johann F
authors.initials: JF
authors.lastname: Görgens
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D011232:Chemical Precipitation; D005052:Eucalyptus / Q000737:chemistry*; D005965:Glucuronates / Q000378:metabolism; D005966:Glucuronidase / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006868:Hydrolysis; D011108:Polymers / Q000737:chemistry / Q000302:isolation & purification; D031786:Saccharum / Q000737:chemistry*; D012995:Solubility; D014783:Viscosity; D014990:Xylans / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: D005965:Glucuronates; D011108:Polymers; D014990:Xylans; C036035:4-O-methylglucuronic acid; D002482:Cellulose; C027433:bagasse; D006026:Glycoside Hydrolases; D005966:Glucuronidase; C019713:alpha-N-arabinofuranosidase
keywords: 4-O-Methyl-D-glucuronic acid; Arabinose; Enzymatic hydrolysis; Hydrogels; Xylan precipitation; α-d-Glucuronidase; α-l-Arabinofuranosidase