The occurrence of sucrose (mt 6.9–7.1 min) could be
explained as remaining after iso-propanol extraction as part
of the bulk of this disaccharide, the main component of
sugarcane juices, but this is not probable, since sucrose
would easily be hydrolyzed by the acid. More probably,
sucrose could be removed from sugarcane heterofructans
by incomplete acidic hydrolysis of the polysaccharide. The
same argument supports the interpretation that the largest
part of glucose, as the main component of the xanthan, was recovered as cellobiose (-D-glucosyl-[14]-D-glucose), as
previously found (11, 14). The use of inoculated sugarcane
tissues for characterizing xanthan has been absolutely required
since X. albilineans does not secrete the polysaccharide
to liquid culture media (unpublished), in contrast to that
described for X. campestris (33). Then, xanthan produced
by X. albilineans is recovered from sugarcane juices previously
inoculated with the pathogen whereas the occurrence
of G. diazotrophicus in sugarcane tissues impedes the production
of this polysaccharide, probably by inhibiting the
growth of Xanthomonas.