PepsiCo seeks to patent ‘biological method for preparing Reb M’
Right now, the focus of many patent applications surrounding stevia is on ways to produce the minor - but better-tasting - steviol glycosides such as Reb D and Reb M in a cost-efficient manner at a commercial scale.
There are multiple approaches, from breeding plants naturally higher in these glycosides, to new extraction techniques, to bypassing the leaf altogether and using genetically engineered microbes to convert sugar into glycosides, or using enzymes to transfer glucose molecules from starches to steviol glycosides extracted from leaves.
In US patent application 20170211113, filed in 2014 and published on July 27, 2017, PepsiCo outlines a method for preparing Reb M – which lacks the bitterness of some of the other glycosides – from Reb A (a glycoside found in larger quantities in the stevia leaf) or D using sugar and enzymes.
“In the presence of sucrose and UDP... Rebaudioside M is generated by means of reaction of the substrate [eg. Reb A] under the catalysis of a mixture of [the enzymes] UDP-glucosyl transferase and sucrose synthetase (AtSUS1), or recombinant cells containing the UDP-glucosyl transferase and sucrose synthetase…”
'The method is suitable for industrialized production'
After the reaction, says PepsiCo, “the reaction solution is centrifuged, then the supernatant is taken, and separated with a macroporous adsorbent resin to obtain a solution of a crude product of Rebaudioside M, which is crystallized in an aqueous ethanol solution, so as to obtain a Rebaudioside M product with a purity greater than 98%.”
Preferably, it says, “the UDP-glucosyl transferase [enzyme] is UGT-A derived from Stevia rebaudiana [ie. from the stevia leaf] and/or UGT-B derived from Oryza sativa [ie. from rice].” However, the enzymes can also be produced via the microorganisms Escherichia coli, Saccharomyces cerevisiae or Pichia pastoris.
It adds: “The method for preparing Rebaudioside M by an enzyme method provided in the present invention has an important application value. Through optimization and controlling of the solubilizer, reaction temperature and pH, the conversion rate and purity are both improved, and the production cost is reduced. Thus, this method is suitable for industrialized production.”
Read the full patent application HERE (‘Method for preparing Rebaudioside M by using enzyme method’)
