Background: The aim of the present study was to evaluate gum productivity of a local strain,
Xanthomonas
axonopodis pv.
vesicatoria, isolated from pepper plant, and its rheological behavior for the first time compared
to the standard strain,
Xanthomonas campestris
DSM 19000 (NRRL B-1459). The influence of operational
conditions (agitation rate and inoculum volume) on gum production and rheological properties of gums from
the
Xanthomonas strains were investigated.
Results: The isolated strain of
Xanthomonas showed similar xanthan yield compared to the standard strain.
Furthermore, this study clearly confirmed that gum yield depended on bacterial strain, agitation rate, and
inoculum size. The most suitable conditions for the gum production in an orbital shaker in terms of agitation
rate and inoculum size were 180 rpm and 5%, respectively, resulting in an average production of 10.96 and
11.19 g/L for
X. axonopodis pv.
vesicatoria and
X. campestris DSM 19000, respectively. Regarding the rheological
properties, Ostwald-de-Waele and power law models were used to describe flow and oscillatory behavior of
the gum solutions, respectively. Consistency of the novel gum solution remarkably was much higher than the
commercial xanthan gum solution. Flow and oscillatory behavior and their temperature ramps showed that
weak gel-like structure could be obtained with less gum concentrations when the novel gum was used.
Conclusion: Therefore, yield and technological properties of the aqueous solutions of the exopolysaccharide
synthesized by
X. axonopodis pv.
vesicatoria were observed to be more suitable for industrial production.
