Immobilisation and stabilisation of β--galactosidase from Kluyveromyces lactis using a glyoxyl support

β-galactosidase from Kluyveromyces lactis was covalently immobilised on a Glyoxyl Sepharose (GS) support by multi-point attachment. The enzyme immobilisation process was very efficient; the supports immobilised almost all the protein responsible for the catalytic activity in a short period of time, retaining approximately 82% of the activity in the case of the optimal immobilised preparations. Stability of the GS derivatives varied as a function of enzyme-support incubation time. The optimal immobilised preparation was produced after 2 h of incubation with the support at alkaline pH. This derivative, obtained by multi-point covalent attachment, was 100-fold more stable at pH 7 and 50 °C than the cyanogen bromide Sepharose derivative obtained by a one-point covalent immobilisation method. Stabilisation was also observed under a wide range of experimental conditions. This method allowed the immobilisation of 9000 IU enzyme g−1 of support, resulting in highly active and stable derivatives suitable for industrial processes.
We thank COLCIENCIAS, Municipio de Rionegro and Universidad de Antioquia for financial support through the program “Becas doctorales 2007 en el convenio de cooperación # 030-2006”. We also thank the Spanish Ministry of Science for financial support through intramural projects (2008801058) and project No. (AGL-2009- 07625).