Abstract
A β-glucosidase gene of Ruminococcus albus was introduced into Zymomonas mobilis NRRL B-14023, ATCC29191 and B69, on a newly constructed vector, a derivative of pZA22, by conjugal transfer with the helper plasmid pRK2013. Z. mobilis strains carrying this gene showed similar levels of intracellular β-glucosidase activity (per culture volume) to Escherichia coli carrying the same gene on pBR322. The stability of a hybrid plasmid carrying the β-glucosidase gene in Z. mobilis was examined through serial transfer tp antibiotic-free medium; 91-93 % after the first transfer and 60-85% after the fourth transfer of the Z. mobilis cells were β-glucosidase-producing ones in which the hybrid plasmid was retained.
