EFFECTS OF AGITATION BY FLAT-BLADED TURBINE IMPELLER ON MICROBIAL PRODUCTION OF XANTHAN GUM

[摘要] References(23)Cited-By(23)The effects of agitation by a flat-bladed turbine impeller on the microbial production of xanthan gum were studied. The results showed that the intensity of shear flow of an impeller was particularly important compared with other physical factors relevant to agitation. It was also observed in an equipment of defined shear rate that the specific production rate of xanthan gum and the specific oxygen uptake rate were influenced by the shear stress but not by the shear rate. Both of these rates increased with increasing shear stress in the range of 0-40 Pa, beyond which they were constant. Increase in glucose concentration, as the driving force of glucose transfer from the medium into the cells, resulted in increase of the specific production rate of xanthan gum. These results suggest that the shear stress was particularly important for xanthan gum production and that the microbial production of xanthan gum might be limited by the mass transfer of the materials from the medium into the cells at low shear stress.

[关键词] Agitation;Biochemical Engineering;Xanthan Gum;Tip Speed;Shear Rate;Shear Stress;Mass Transfer