Merck + Co., Inc.

Richard A Empey

Joseph S Racciato

Ian W Cottrell

David J Pettitt

Jurgen G Dominik

A novel process is described for making a low calcium xanthan gum exhibiting smooth flow properties which comprises the use of high levels of phosphate in the fermentation medium.

High phosphate process for making low calcium, smooth flow xanthan gum

A water-soluble anionic graft copolymer of xanthan gum and polyacrylamide wherein at least part of the amide function is sulfomethylated.

Sulfomethylated graft copolymers of xanthan gum and polyacrylamide

Intimate intermingling, as in a tumble reactor, of wet particulate xanthan gum, with either propylene oxide, .beta.-propiolactone, glutaraldehyde or pivalolactone, as essentially the only gas present, at about 40.degree.-70.degree. C., for from 1-5 hours, produces xanthan gum in which the cellulase enzyme is inactivated, but in which the viscosity of solutions is increased; the propylene oxide is removed to afford a residual propylene oxide content of not more than 300 ppm in the product xanthan gum.

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Okmulgee, OK, United States of America

Richard A Empey