Recovery of steviol glycosides

Abstract

The present invention relates a process for the recovery of one or more steviol glycosides from a steviol glycoside-containing fermentation broth, which method comprises (a) providing a fermentation broth comprising one or more steviol glycosides and one or more non-steviol glycoside components; (b) separating the liquid phase of the broth from the solid phase of the broth; (c) providing an adsorbent resin; (d) contacting the liquid phase of the broth with the adsorbent resin in order to separate at least a portion of the one or more steviol glycosides from the non-steviol glycoside components, thereby to recover one or more steviol glycosides from the fermentation broth containing one or more steviol glycosides. The invention also relates to a purified steviol glycoside composition prepared using such a process.

1 . A process for the recovery of one or more steviol glycosides from a steviol glycoside-containing fermentation broth, which method comprises
 (a) providing a fermentation broth comprising one or more steviol glycosides and one or more non-steviol glycoside components;   (b) separating a liquid phase of the broth from a solid phase of the broth;   (c) providing an adsorbent resin;   (d) contacting the liquid phase of the broth with the adsorbent resin in order to separate at least a portion of the one or more steviol glycosides from the non-steviol glycoside components,   thereby to recover one or more steviol glycosides from the fermentation broth containing one or more steviol glycosides.   
     
     
         2 . A process according to  claim 1 , wherein the adsorbent resin is provided in a packed column. 
     
     
         3 . A process for the recovery of one or more steviol glycosides from a steviol glycoside-containing fermentation broth, which method comprises
 (a) providing a steviol glycoside-containing fermentation broth;   (b) providing an adsorbent resin;   (c) contacting the broth with the adsorbent resin in order to separate at least a portion of the one or more steviol glycosides from the non-steviol glycoside components,   
       thereby to recover one or more steviol glycosides from the fermentation broth containing one or more steviol glycosides. 
     
     
         4 . A process according to  claim 3 , wherein the adsorbent resin is provided in a packed column in an expanded bed mode. 
     
     
         5 . A process according to  claim 2 , wherein the adsorbent resin is a polystyrene-divinylbenzene resin, a polymethacrylate resin, a polyaromatic resin, a functionalized polymethacrylate-divinybenzene resin, a functionalized polystyrene-divinylbenzene resin or an amino (NH2) bonded methacrylate/divinylbenzene copolymer resin. 
     
     
         6 . A process according to  claim 1 , wherein the method of separating comprises adsorb/desorb chromatography. 
     
     
         7 . A process according to  claim 6 , wherein the adsorb/desorb chromatography comprises
 (a) providing a liquid phase or a broth and a solvent;   (b) providing an adsorbent resin;   (c) providing an elution solvent;   (d) contacting the adsorbent resin with the liquid phase or broth and elution solvent so that at least a portion of the non-steviol glycoside components adsorbs onto the adsorbent enriching the glycoside solution in steviol glycosides and resulting in the formation of a purified steviol glycoside composition that is eluted from the adsorbent along with the elution solvent; and   (e) optionally, desorbing the non-steviol glycoside components from the adsorbent.   
     
     
         8 . A process according to  claim 7 , wherein the adsorbent resin is provided in a packed column. 
     
     
         9 . A process according to  claim 7 , wherein the elution solvent comprises about 20% weight or less alcohol, optionally comprising ethanol; and about 80% weight or greater water. 
     
     
         10 . A process according to  claim 7 , wherein the elution solvent comprises about 50% weight or less alcohol, such as optionally comprising ethanol; and about 50% weight or greater water. 
     
     
         11 . A process according to  claim 1 , wherein the method of separating comprises fractionation chromatography. 
     
     
         12 . A process according to  claim 11 , wherein the fractionation chromatography comprises:
 (a) providing a liquid phase or a broth and a solvent;   (b) providing an adsorbent; and   (c) contacting the adsorbent with the liquid phase or broth so that at least a portion of non-steviol glycoside components adsorb onto the adsorbent and so that at least a portion of steviol glycoside adsorbs onto the adsorbent, wherein steviol glycosides propagate through the adsorbent at a faster rate than non-steviol glycosides; and   (d) collecting a steviol glycoside-containing solution from the adsorbent.   
     
     
         13 . A process according to  claim 12 , wherein the adsorbent is provided in a packed column. 
     
     
         14 . A process according to  claim 12 , wherein the solvent comprises about 20% weight or greater alcohol, optionally comprising ethanol, and about 80% weight or less water. 
     
     
         15 . A process according to  claim 12 , wherein the solvent comprises about 25% to about 35% weight alcohol, optionally comprising ethanol, and about 65% to about 75% water. 
     
     
         16 . A process according to  claim 12 , wherein the solvent comprises water and wherein the adsorbent is a strongly acidic cationic exchange resin. 
     
     
         17 . A process according to  claim 1 , wherein the adsorbent has a surface area of about 900 m 2 /gram or greater. 
     
     
         18 . A process according to  claim 5 , wherein the adsorbent is functionalized with one or more tertiary amines or quaternary amines. 
     
     
         19 . A process according to  claim 1 , wherein the recovered steviol glycoside-containing solution has a purity that is at least about 10% greater as compared to a purity of the liquid phase or broth. 
     
     
         20 . A process according to  claim 1 , wherein the purified steviol glycoside-containing solution comprises, on a dry solids basis, at least about 95% weight of Rebaudioside A, Rebaudioside D or Rebaudioside M. 
     
     
         21 . A process according to  claim 1 , wherein the steviol glycoside-containing solution is spray-dried to provide a powder. 
     
     
         22 . A solution comprising one or more steviol glycosides obtainable by a process according to  claim 1 . 
     
     
         23 . A solution according to  claim 22  which comprises one or more of steviolmonoside, steviolbioside, stevioside or rebaudioside A, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside E, rebaudioside F, rubusoside, dulcoside A or rebaudioside M. 
     
     
         24 . A solution according to  claim 22  which comprises, on a dry solids basis, at least about 95% weight of Rebaudioside A, Rebaudioside D or Rebaudioside M. 
     
     
         25 . A composition which comprises at least about, on a dry solids basis, at least about 95% fermentatively-produced Rebaudioside A, Rebaudioside D or Rebaudioside M. 
     
     
         26 . A composition according to  claim 25  which is a powder obtainable by a process wherein the steviol glycoside-containing solution is spray-dried to provide a powder.