Cross-linked enzyme aggregates of naringinase: novel biocatalysts for naringin hydrolysis.

Cross-linked enzyme aggregates (CLEAs) have emerged as interesting biocatalyst design for immobilization. These new generation enzyme biocatalysts, CLEAs, in addition to exhibiting good mechanical stability, can be highly active, since they do not include large amounts of foreign particulate nonenzymatic material and may have increased stability. Naringinase (NGase) is an enzyme complex with high potential in pharmaceutical and food industries. In fact, NGase can be used in the biotransformation of steroids, of antibiotics and mainly on glycosides hydrolysis. In this paper, the formation of CLEAs was tried using ammonium sulphate, polyethylene glycol 6000 and tert-butyl alcohol as precipitant agents and glutaraldehyde as cross-linking agent, at different pH, time, and temperature conditions. However, among the precipitant agents tested, only tert-butyl alcohol cross-linked with glutaraldehyde allowed the formation of CLEAs, at pH 4.0 and at temperature between 7 and 10°C. Different enzyme loadings were tested. The NGase-CLEAs were highly effective in naringin hydrolysis. The operational stability of the NGase-CLEAs aggregates was studied through six successive reutilizations.