18-05: Direct enzymatic acrylation of maltooligosaccharides

Sugar acrylates are promising monomers to get polymers within high absorption properties because of the portion acrylate and besides that with renewable resource. Enzymatic direct acrylation without addition of protective groups was highly selective to produce monoacrylate of the fructose. Although the solubility of carbohydrates in organic solvents, which allow enzymatic activity, is low, it is possible to shift the equilibrium to the esterification with low water content, supersaturated solutions of sugar and excess of acrylic acid.  Increasing the chain of the glucose units for those acrylate polymers would increase their biodegradability, however decrease the solubility in those solvents. Thus, the acrylation of fructose at 328K in tert-butanol as solvent with commercial immobilized lipase B from Candida antarctica under initial maximum solubility of fructose (0.1M) and supersaturated system - three times of the respective solid amount has been added to keep the fructose available continuously - until 24h was investigated. The production of monoacrylate have increase from 12gL^-1 to 39g L^-1 with continuous maximum availability of fructose.

The purpose of this work was to observe the direct enzymatic acrylation of the maltose, maltotriose, as well of the commercial maltodextrin (DP= 5) in the same conditions (solvent, temperature, lipase and supersaturated system). From time-course studies of the heterogeneous system was possible observe a growing peak area at the HPLC analysis for those di-, tri- and oligosaccharides. Apart from this, ESI-MS confirmed the presence of mono- until tetra- substituted hydroxyls for maltose and maltotriose.