Application of statistical method to evaluate immobilization variables of trypsin entrapped with sol-gel method

Bioimmobilization with sol-gel method is a complicate system, involving many parameters that can affect sol-gel structure and immobilized biomolecules activity. In this study, trypsin, a model enzyme, was entrapped into sol-gel glasses produced from tetraethoxysilane (TEOS) and water to study the relationships between the immobilization parameters, namely ratio of water to TEOS, volume of poly (ethylene glycol) (PEG), concentration of buffer solution, pH of buffer solution by using statistical methods. Two regression equations and analysis of variance (ANOVA) were obtained with the entrapped enzyme activity and enzyme loading yield as the response values, respectively. Statistical calculations showed that the effects of the four variables on the entrapped enzyme activity and enzyme loading yield were different. Entrapped trypsin activity (35.6%) and trypsin loading yield (68.3%) were obtained by using optimized immobilization conditions. The results of this study may help to manipulate the properties of sol-gel to get high immobilization efficiency. Keywords: Sol-Gel, Trypsin, Enzyme, Entrapment, Response surface methodology Received: 06 February 2009 / Received in revised form: 08 March 2009, Accepted: 11 May 2009, Published online: 16 May 2009