title: Genetic Construction of Lactose-Utilizing Xanthomonas campestris.
abstract: Xanthomonas campestris, the producer of xanthan gum, possesses a beta-galactosidase of very low specific activity. Plasmid pGC9114 (RP1::Tn951), generated by the transposition of the lactose transposon Tn951 to RP1, was conjugally transferred into XN1, a nalidixic acid-resistant derivative of X. campestris NRRL B-1459S-4L. Transfer occurred on membrane filters and in broth. The beta-galactosidase gene of Tn951 was expressed in X. campestris. The specific activity of beta-galactosidase in transconjugants was over 200-fold higher than that in XN1, and transconjugants grew as well in lactose-based media as in glucose-based media. The lactose-utilizing transconjugants could potentially be used to produce xanthan gum from cheese whey.
authors.affiliation: Agricultural Research Service, Eastern Regional Research Center, U.S. Department of Agriculture, Philadelphia, Pennsylvania 19118.
authors.forename: P M
authors.initials: PM
authors.lastname: Walsh
authors.forename: M J
authors.initials: MJ
authors.lastname: Haas
authors.forename: G A
authors.initials: GA
authors.lastname: Somkuti