Immobilization of Zymomonas mobilis in silica from the rice husk ash

The purpose of this study were to preliminary study of immobilization of Zymomonas mobilisin silica from rice husk ask Zymomonas mobilis is an important microbe on bioethanol production. In this study, silica was contacted with inoculum of Zymomonas mobilis at various time, ratio of silica:cells and speed of shaker at room temperature. The results showed that Zymomonas mobilis can be immobilized in silica. The contact time and the ratio between the number of cells and the mass of the silica during immobilization affected the percentage of immobilized cells, while the speed of shaker was not. The optimum results achieved in this study were 38 %, achieved with the used of 0.2 g of silica matrix with 10 mL of a cell solution having an absorbance of 0.85 for a contact time of 30 min. Immobilized Zymomonas mobilis in silica could conduct the ethanol fermentation. These results suggest that silica werepotential matriks for immobilizing Zymomonas mobilis.