G76E is a non-mucoid mutant derived from Xanthomonas campestris pv. campestris 17 by Tn mutagenesis. A 3.0-kb EcoRI-KpnI fragment, cloned from a genomic bank of Xc17, was able to complement G76E and caused an increase of xanthan production by ca. 46% over Xc17. This 3.0-kb EcoRT-KpnI fragment insert was different from the two previously cloned EcoRI fragments from Xc17 that also increased xanthan production.