Beta-glucanase productivity improvement via cell immobilization of recombinant Escherichia coli cells in different matrices

The studies have been performed to analyze the production of β-glucanase by a recombinant strain of Escherichia coli immobilized in different 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. The 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). Different 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.