β-glucanase Productivity Improvement via Cell Immobilization of Recombinant Escherichia coli Cells in Di"erent Matrices

"e studies have been performed to analyze the production of β-glucanase by a recombinant strain of Escherichia coli immobilized in di#erent matrices. Porous sintered glass SIRAN®, Ceramic supporting matrices and Broken Pumice stone as well as SIRAN Raschig-rings were examined for the immobilization of whole bacterial cells. "e β-glucanase activity of bacteria immobilized in CeramTec PST 5 (4–5 mm) was very low. CeramTec PST 5 (1.5–2.5 mm) was found to be the best carrier compared to all other matrices regarding glucanase production (630 U/ml) and compared to enzyme activity produced by free cells (500 U/ml). Di#erent doses of matrices were applied (2, 5, 7, 10 g/lask) in the form of “matrix weight”. Using 2 g/flask of CeramTec PST 5 (1.5–2.5 mm) yielded enzyme activity of 630 U/ml). CeramTec gives highest operational stability of β-glucanase by repeated batch fermentation to 5 cycles, and activity reached 660 U/ml. Scanning electron microscopy observations showed a high number of vegetative cells that continued growth inside the matrices, indicating that β-glucanase activity improvement was due to the immobilization of the cells. K e y w o r d s: β-glucanase, organic and/or inorganic matrices, cell immobilization, scanning electron microscope * Corresponding author: U. Beshay, Mubarak City for Scientific Research and Technology Applications, Bioprocess Development Depart ment, New Bourg El-Arab City, Universities and Research District; 21934 Alexandria, Egypt; phone: +2 03 4593 422; fax: +2 03 4593 407; e-mail: [email protected]; u.beshay@mucsat,sci.eg Beshay U. et al. 2 134