Supplementation of commercial cocktail with endo-arabinanase of Bacillus licheniformes

An essential step in the conversion of lignocellulosic biomass to ethanol or other by-products biorefinery is the depolymerization of polysaccharides constituents to fermentable sugars by enzymatic pathway. Polysaccharides containing L-arabinose residues are found as constituents of plant cell walls.  They are found as either homoglycans, arabinans or heteroglycans such as arabinoxylans and arabinogalactans. Arabinanases (ABNA) are one of the enzymes responsible for hydrolase arabinan. The aim of this work was to evaluate the supplementation of commercial enzyme cocktail Cellic with endo-arabinanase of Bacillus licheniformes.  For this purpose the enzyme was cloned and expressed in E. coli system and the biochemistry and biophysical characterization was performed. The results indicate that the catalytic activity of the enzyme was enhanced in the presence of divalent ions and are strongly inhibited by Cu2+, Zn2+ e Fe3+ (5 mM). The optimum pH and temperature range for activity were 5.5 to 6.5 and 35 to 40 ˚ C, respectivelly. The enzyme was able to increase by 15% the hydrolysis of cane sugar biomass when supplemented to Cellic cocktail despite support only 1 hour at 50 °C .  The enzyme stability was increased in 128 times when immobilized with glyoxyl agarose. So, arabinanase demonstrate the importance of pectin side chains hydrolysis when compared to cocktail without supplementation.