Biological upgrading of wastes from sucrose processing

The aim of this study is to examine the production of fructose syrups and gluconic acid in a two-step process catalyzed by biocatalysts (enzymes or cells) that are immobilized in hydrogels of poly-(2-hydroxyethylmethacrylate). These polymers (poly-HEMA) can be prepared quite easily under mild conditions of both temperature (4°C) and concentration of chemicals (monomer, cross-linking agent, reaction initiators). Either free invertase or Saccharomyces cerevisiae cells and glucose oxidase were immobilized in hydrogels of poly-HEMA. The experimental investigation indicates that the first reaction step, namely, the hydrolysis of sucrose, can be carried out with immobilized cells of Saccharomyces cerevisiae. The results of this are already satisfactory. However, the second reaction step, namely, the conversion of glucose into gluconic acid, needs further developments for the preparation of hydrogels with higher activity yields and for the optimization of reaction conditions.