Xanthan production

Explain briefly why the rate of xanthan production increases during the production phase while that of sucdnoglycan remains constant... 

Papagianni, M., Psomas, S. K., Batsilas, L., Paras, S., Kyriakidis, D. A., and Liakopoulou Kyriakides, M. (2001). Xanthan production by Xanthomonas campestris in batch cultures. Process Biochem. 37, 73-80. 

Stredansky, M. and Conti, E. (1999). Xanthan production by solid state fermentation. Process Biochem. 34, 581-587. 

Tseng, Y.H., Ting, W.Y., Chou, H.C., Yang, B.Y. et al (1992) Increase of xanthan production by cloning xps genes into wild-type Xanthomonas campestris. Lett. Appl Microbiol, 14, 43-46. 

Sandford, P. A., J.E. Pittsley, C.A. Knutson, P R Watson, M.C. Cadmus, and A. Jeanes, Variation in Xanthomonas campestris NRRL B-1459 Characterization of Xanthan Products of Differing Pyrubic Acid Compound, ACS Symposium Series No. 45, Extracellular Microbial Polysaccharides P.A. Sandford and A. Laskin, Eds., American Chemical Society, New York... 

Weisrock, W.P. (Standard Oil Company, Indiana), Method for Improving Specific Xanthan Productivity During Continuous Fermentation, U.S. Patent 4,311,796 (January 19, 1982). 

Xanthan samples from four commercial manufacturers were studied in synthetic reservoir brines and a dilute NaCl solution. The samples included broth and powdered xanthan products. The weight-average molecular weight, M, for each sample was measured in the different solvents by low angle light scattering. was not affected by the brine composition, and no... 

Funahashi, H., K. I. Hiral, T. Yoshida, H. Taguchi, Mechanistic Analysis of Xanthan Production in a Stirred Tank, J. Ferment. TechnoL, 66, 355, (1988). 

Suh et al. [80] 150 Xanthan products 0.125-0.2 20-33 Production of xanthan in a concentric tube reactor and measured holdup and mass transfer coefficients at various stages of reaction. 

Ash et al. (1983) studied the chemical stability of xanthan and one novel heteropolysaccharide which they do not identify. They note the earlier findings of Davison and Mentzer (1980), who observed less than 30% loss in viscosity over 500 days at 90 "C in sea water, and the results of Sutherland et al (1986), who found little loss in viscosity at 112" C in 6% brine over 42 days. Ash et al (1983) found considerable variation in stability of xanthan products obtained from different sources. They, like other workers, noted an increase in viscosity over the first few days of the test which has been ascribed to delayed hydration of the polymer. They also noted that the stability of one of the xanthan samples depended strongly on the salinity of the test brine as shown in Figure 4.8. The data in Figure 4.8 refer to stability at 70°C, but a similar pattern is found at 90°C. This increased stability with increasing salinity gave one clue to one of the physical factors which may influence stability—namely the order-disorder (or helix-coil) transition, as... 

Figure 18-15 Effect of the cavern volume (expressed as a percentage of the total broth volume) on the specific xanthan productivity ( ) SRGT ( ) LRT (A) PMD ( ) SRT. (From Amanullah et ah, 1998b.)...

Galindo, E. (1994). Aspects of the Process for Xanthan Production, Trans. Inst. Chem. Eng., Part C, 72, 227-237. 

Herbst, H., A. Schumpe, and W. Deckwer (1992). Xanthan production in stirred tank fermenters oxygen transfer and scale up, Chem. Eng. Technol, 15, 425-434. 

Peters, H. U., H. Herbst, P. G. M. Heselink, H. Lunsdorf, A. Schumpe, and W. D. Deck-wer (1989a). The influence of agitation rate on xanthan production by Xanthomonas campestris. Biotechnol Bioeng., 34, 1393-1397. 

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