Genetic control of acetylation and pyruvylation of xanthan based polysaccharide polymers

Abstract

Variant xanthan gums are provided which include a water-soluble polysaccharide polymer comprising repeating pentamer units having a D-glucose:D-mannose:D-glucuronic acid ratio of about 2:2:1, and a water-soluble polysaccharide polymer comprising repeating tetramer units having a D-glucose:D-mannose:D-glucuronic acid ratio of about 2:1:1. The D-glucose moieties are linked in a beta-[1,4] configuration. The inner D-mannose moieties are linked in an alpha-[1,3] configuration, generally to alternate glucose moieties. The D-glucuronic acid moieties are linked in a beta-[1,2] configuration to the inner mannose moieties. The outer mannose moieties are linked to the glucuronic acid moieties in a beta-[1,4] configuration. Processes for preparing the polysaccharide polymers are also provided.

What is claimed is:  
     
         1 . A water-soluble polysaccharide polymer comprising repeating pentamer units having a D-glucose:D-mannose:D-glucuronic acid ratio of about 2:2:1, wherein the D-glucose moieties are linked in a beta-[1,4] configuration, inner D-mannose moieties are linked in an alpha-[1,3] configuration primarily to alternate glucose moieties, the D-glucuronic acid moieties are linked in a beta-[1,2] configuration to said inner mannose moieties, and outer mannose moieties are linked to said glucuronic acid moieties in a beta-[1,4] configuration.  
     
     
         2 . The polysaccharide polymer of  claim 1 , wherein said inner mannose moieties are acetylated.  
     
     
         3 . The polysaccharide polymer of  claim 2 , wherein said outer mannose moieties are acetylated.  
     
     
         4 . The polysaccharide polymer of  claim 1 , wherein a portion of said outer mannose moieties are pyruvylated and the remainder are acetylated.  
     
     
         5 . The polysaccharide polymer of  claim 2 , wherein substantially all of said outer mannose moieties are pyruvylated.  
     
     
         6 . The polysaccharide polymer of  claim 1 , wherein said outer mannose moieties are pyruvylated.  
     
     
         7 . The polysaccharide polymer of  claim 1 , wherein said outer mannose moities are acetylated.  
     
     
         8 . A water-soluble polysaccharide polymer comprising repeated tetramer units having a D-glucose:D-mannose:D-glucuronic acid ratio of about 2:1:1 wherein (1) the D-glucose moieties are linked in a beta-[1,4] configuration, (2) the D-mannose moieties, acetylated or not acetylated at the 6-0 position, are linked in an alpha-[1,3] configuration primarily to alternate glucose moieties, and (3) the D-glucuronic acid moieties, and (3) the D-glucuronic acid moieties are linked in a beta-[1,3] configuration to the mannose moieties.  
     
     
         9 . The polysaccharide polymer of  claim 8 , wherein the mannose moieties of the polysaccharide polymer are acetylated at the 6-0 position.  
     
     
         10 . The polysaccharide polymer of  claim 8 , wherein the mannose moieties of the polysaccharide polymer are not acetylated at the 6-0 position.  
     
     
         11 . The polysaccharide polymer of  claim 8 , wherein at least 90% of the mannose moieties of the polysaccharide polymer are acetylated at the 6-0 position.  
     
     
         12 . A process for preparing the polysaccharide polymer of  claim 1  comprising: 
 inoculating a suitable growth medium with a microorganism of the genus Xanthomonas which is capable of synthesizing the polysaccharide polymer of  claim 1  that is non-acetylated at the inner mannose and is non-acetylated and non-pyruvylated at the outer mannose, and  
 incubating said inoculated growth medium at a suitable temperature, pH and dissolved oxygen level for a time sufficient to produce the polysaccharide polymer of  claim 1 .  
 
     
     
         13 . A process for preparing the polysaccharide polymer of  claim 2  comprising: 
 inoculating a suitable growth medium with a microorganism of the genus Xanthomonas which is capable of synthesizing the polysaccharide polymer of  claim 2  that is acetylated at the inner mannose and is non-acetylated and non-pyruvylated at the outer mannose, and  
 incubating said inoculated growth medium at a suitable temperature, pH and dissolved oxygen level for a time sufficient to produce the polysaccharide polymer of  claim 2 .  
 
     
     
         14 . A process for preparing the polysaccharide polymer of  claim 3  comprising: 
 inoculating a suitable growth medium with a microorganism of the genus Xanthomonas which is capable of synthesizing the polysaccharide polymer of  claim 3  that is acetylated at the inner mannose and is acetylated and non-pyruvylated at the outer mannose, and incubating said inoculated growth medium at a suitable temperature, pH and dissolved oxygen level for a time sufficient to produce the polysaccharide polymer of  claim 3 .  
 
     
     
         15 . A process for preparing the polysaccharide polymer of  claim 4  comprising: 
 inoculating a suitable growth medium with a microorganism of the genus Xanthomonas which is capable of synthesizing the polysaccharide polymer of  claim 4  that is non-acetylated at the inner mannose and is acetylated and pyruvylated at the outer mannose, and  
 incubating said inoculated growth medium at a suitable temperature, pH and dissolved oxygen level for a time sufficient to produce the polysaccharide polymer of  claim 4 .  
 
     
     
         16 . A process for preparing the polysaccharide polymer of  claim 5  comprising: 
 inoculating a suitable growth medium with a microorganism of the genus Xanthomonas which is capable of synthesizing the polysaccharide polymer of  claim 5  that is acetylated at the inner mannose and is pyruvylated but non-acetylated at the outer mannose, and  
 incubating said inoculated growth medium at a suitable temperature, pH and dissolved oxygen level for a time sufficient to produce the polysaccharide polymer of  claim 5 .  
 
     
     
         17 . A process for preparing the polysaccharide polymer of  claim 6  comprising: 
 inoculating a suitable growth medium with a microorganism of the genus Xanthomonas which is capable of synthesizing the polysaccharide polymer of  claim 6  that is non-acetylated at the inner mannose and is pyruvylated but non-acetylated at the outer mannose, and  
 incubating said inoculated growth medium at a suitable temperature, pH and dissolved oxygen level for a time sufficient to produce the polysaccharide polymer of  claim 6 .  
 
     
     
         18 . A process for preparing the polysaccharide polymer of  claim 7  comprising: 
 inoculating a suitable growth medium with a microorganism of the genus Xanthomonas which is capable of synthesizing the polysaccharide polymer of  claim 7  that is non-acetylated at the inner mannose and is acetylated but not pyruvylated at the outer mannose, and  
 incubating said inoculated growth medium at a suitable temperature, pH and dissolved oxygen level for a time sufficient to produce the polysaccharide polymer of  claim 7 .  
 
     
     
         19 . A process for preparing the polysaccharide polymer of  claim 8  which comprises; 
 inoculating a suitable growth medium with a microorganism of the genus Xanthomonas which is capable of synthesizing a polytetramer gum of  claim 8 , and  
 incubating the inoculated growth medium at suitable temperature, pH and dissolved oxygen levels to produce a polysaccharide polymer having a D-glucose:D-mannose:D-glucuronic acid ratio of about 2:1:1.  
 
     
     
         20 . The process of  claim 19  wherein the polysaccharide polmer is recovered from the growth medium by precipitation or ultrafiltration.  
     
     
         21 . The process of  claim 19  wherein the microorganism is of the species  Xanthomonas campestris.    
     
     
         22 . The process of  claim 19  wherein the microorganism is a Transferase V deficient mutant of  Xanthomonas campestris.    
     
     
         23 . The process of  claim 19  wherein the microorganism is a Transferase V and Acetylase deficient mutant of  Xanthomonas campestris.    
     
     
         24 . The process of  claim 19  wherein the microorganism is a Transferase V and acetyl coenzyme A deficient mutant of  Xanthomonas campestris.    
     
     
         25 . The process of  claim 19  wherein the microorganism is a phosphoenolpyruvate deficient mutant of  Xanthomonas campestris.    
     
     
         26 . A process for preparing the polysaccharide polymer of  claim 11  which comprises; 
 inoculating a suitable growth medium with a microorganism of the genus Xanthomonas which is capable of synthesizing a polytetramer gum of  claim 11 , and  
 incubating the inoculated growth medium at suitable temperature, pH and dissovled oxygen levels to produce a polysaccharide polymer having a D-glucose:D-mannose:D-glucuronic acid ratio of about 2:1:1 wherein said polymer is not acetylated.  
 
     
     
         27 . The process of  claim 12 , wherein said microorganism is a Ketalase, Acetylase I, and Acetylase II deficient mutant of  Xanthomonas campestris.    
     
     
         28 . The process of  claim 13 , wherein said microorganism is a Ketalase and Acetylase II deficient mutant of  Xanthamonas campestris.    
     
     
         29 . The process of  claim 14 , wherein said microorganism is a Ketalase deficient mutant of  Xanthomonas campestris.    
     
     
         30 . The process of  claim 15 , wherein said microorganism is an Acetylase I deficient mutant of  Xanthomonas campestris.    
     
     
         31 . The process of  claim 16 , wherein said microorganism is an Acetylase II deficient mutant of  Xanthomonas campestris.    
     
     
         32 . The process of  claim 17 , wherein said microorganism is an Acetylase I and Acetylase II deficient mutant of  X campestris.    
     
     
         33 . The process of  claim 18 , wherein said microorganism is an Acetylase I and Ketalase deficient mutant of  X campestris.    
     
     
         34 . The process of  claim 26  wherein the microorganism is an Acetylase deficient mutant of  Xanthomonas campestris.    
     
     
         35 . The process of  claim 26  wherein the microorganism is ATCC No. 53473, an Acetylase deficient mutant of  Xanthomonas campestris,  (X1006).  
     
     
         36 . A process for preparing the polysaccharide polymer of  claim 1  comprising: 
 inoculating a suitable growth medium with a microorganism of the genus Xanthomonas which contains a chromosomal deletion mutation and is capable of synthesizing the polysaccharide polymer of  claim 1  that is non-acetylated at the inner mannose and is non-acetylated at the outer mannose, and incubating said inoculated growth medium at a suitable temperature, pH and dissolved oxygen level for a time sufficient to produce the polysaccharide polymer of  claim 1 .  
 
     
     
         37 . The process of  claim 36  wherein the microorganism is of the species  Xanthomonas campestris.    
     
     
         38 . The process of  claim 36  wherein the microorganism contains an Acetylase I and II chromosomal deletion mutation.  
     
     
         39 . The process of  claim 36  wherein the microorganism is an Acetylase I and II chromosomal deletion mutant of  Xanthomonas campestris  (X1910).