Xanthan production in stirred tank fermenters: Oxygen transfer and scale‐up

Abstract

The microbial polysaccharide xanthan was produced by cultivation of Xanthomonas campestris in four stirred tanks with volumes ranging from 0.072 to 3 m3. Many of the previously suggested correlations for the volumetric mass transfer coefficient described the present data very unsatisfactorily. When Rushton turbines were employed as stirrers, the experimental results agreed well with a correlation suggested by Kawase and Moo-Young; for the more energy-efficient INTERMIG impellers, this correlation was modified by a factor of three. Constant specific oxygen transfer rate was found to be the appropriate scaleup criterion for constant space-time yield and constant product quality, specifically, the molar mass which determines the viscosity yield.

Mixing in the Fermentation and Cell Culture Industries

“…Ever since xanthan gum was reported by Rogovin et al (1961), considerable research has been devoted to addressing the problems of poor bulk mixing and low oxygen transfer rates in xanthan gum fermentations (Moraine and Rogovin, 1973;Nienow, 1984;Funahashi et al, 1987aFunahashi et al, ,b,c, 1988aNienow and Elson, 1988;Peters et al, 1989aPeters et al, ,b, 1992Galindo andNienow, 1992, 1993;Herbst et al, 1992;Flores et al, 1994;Zhao et al, 1991Zhao et al, , 1994. It is generally agreed in the literature that the process bottleneck in highly productive xanthan fermentations is related to these two parameters.…”

Agitator speed and dissolved oxygen effects in Xanthan fermentations

“…There is gathering evidence that the specific Xanthan production rate is directly related to the specific oxygen uptake rate (Amanullah et al, 1997;Herbst et al, 1992;Peters et al, 1989b;Suh et al, 1990Suh et al, , 1992, which in turn is linked to agitation conditions that determine the total amount of cells participating in the fermentation and the DOT experienced by them. Flores et al (1994) conducted Xanthan fermenta- Figure 8.…”

“…Ever since Xanthan gum was first reported by Rogovin et al (1961), considerable research has been devoted to address the problems of poor bulk mixing and low oxygen transfer rates in Xanthan gum fermentations (Flores et al, 1994;Funahashi et al, 1987bFunahashi et al, , 1988aFunahashi et al, , 1988bNienow, 1992, 1993;Herbst et al, 1992;Nienow, 1984;Nienow and Elson, 1988;Moraine and Rogovin, 1973;Peters et al, 1989aPeters et al, , 1989bPeters et al, , 1992Zhao et al, 1994). It is generally agreed upon in the literature that the process bottleneck in highly productive Xanthan fermentations is related to these two parameters.…”

Polysaccharide production: Experimental comparison of the performance of four mixing devices

“…The viscosity of the broth was considered as a quality indicator since the desired property of a polysaccharide is its viscosity producing power [11].…”