Efficient immobilization of whole cells of Methylomonas sp. strain GYJ3 by sol–gel entrapment

The whole cells of Methanotrophic bacteria Methylomonas sp. strain GYJ3 immobilized by the sol–gel technique was investigated in the present work. After the cells were immobilized by entrapment in sodium silicate sol–gel matrix, a higher activity for propylene epoxidation were observed at a common loading amount. In a batch reaction system, the immobilized cells can be repeatedly used for more than 25 times and no significant loss of the activity was found. The activity was well preserved when the immobilized cells were stored at 4 °C for 45 days. Determination of optimal reaction conditions showed that the immobilized cells took on increased activity at a higher pH and temperature. However, the cells entrapped in methyltrimethoxysilane (MTMS) gel matrix gave a lower activity as compared to that of the free cells. Our experimental results indicate that the sol–gel entrapment based on silica matrixes was a simple, efficient and cost-efficient method for the immobilization the whole cells of Methylomonas sp. strain GYJ3 cells.