DCT
8:18-cv-01679
PureCircle USA Inc v. SweeGen Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: PureCircle USA Inc. (Delaware) and PureCircle Sdn Bhd (Malaysia)
- Defendant: SweeGen, Inc. (Nevada) and Phyto Tech Corp. d/b/a Blue California (California)
- Plaintiff’s Counsel: DLA Piper LLP (US); Hatch, James, & Dodge, P.C.
- Case Identification: 8:18-cv-01679, C.D. Cal., 02/18/2020
- Venue Allegations: Venue is alleged to be proper based on Defendants maintaining a regular and established place of business within the Central District of California.
- Core Dispute: Plaintiff alleges that the process used by Defendants to manufacture their "Bestevia" Rebaudioside M sweetener infringes patents related to biocatalytic methods for producing specific steviol glycosides.
- Technical Context: The technology lies in the food science field of non-caloric sweeteners, specifically using enzymatic processes to convert naturally occurring stevia compounds into other, more desirable high-purity sweeteners for the food and beverage market.
- Key Procedural History: The complaint alleges that Defendants' licensor, Conagen, Inc., cited the ’273 Patent during the prosecution of its own U.S. Patent No. 10,023,604, which allegedly covers the accused process. The complaint also relies heavily on technical disclosures made by Defendants in FDA Generally Recognized as Safe (GRAS) Notice No. 667 and a subsequent supplement to establish the details of the accused manufacturing process.
Case Timeline
| Date | Event |
|---|---|
| 2012-05-22 | Earliest Priority Date for '273 and '257 Patents |
| 2014-08-26 | '273 Patent Application Filed |
| 2016-01-26 | '273 Patent Issues |
| 2016-08-09 | Defendant Blue California files GRAS Notice (GRN) No. 667 |
| 2017-01-06 | '257 Patent Application Filed |
| 2017-02-21 | Defendant SweeGen announces commercialization of "Bestevia" |
| 2018-07-17 | Conagen '604 Patent Issues |
| 2019-11-01 | Defendant Blue California files GRN No. 667 Supplement |
| 2019-11-26 | '257 Patent Issues |
| 2020-02-18 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,243,273 - "Method for Making Rebaudioside X"
- Issued: January 26, 2016 (Compl. ¶¶ 19-20).
The Invention Explained
- Problem Addressed: The patent addresses the need for "simple, efficient, and economical methods" for creating compositions of highly purified steviol glycosides, which are used as high-intensity, non-caloric sweeteners (’273 Patent, col. 2:55-59).
- The Patented Solution: The invention is a biocatalytic process that uses an enzyme, UDP-glucosyltransferase, to convert a specific precursor steviol glycoside (Rebaudioside D) into a target steviol glycoside, Rebaudioside X, which is noted for its desirable sweetener properties (’273 Patent, col. 3:19-25; Abstract). The process is designed to achieve a high degree of conversion, resulting in a highly purified final product.
- Technical Importance: This enzymatic conversion method allows for the targeted production of rare but desirable steviol glycosides that are difficult to extract in high purity from the stevia plant itself, thereby enabling the creation of better-tasting sugar substitutes (Compl. ¶¶ 29-30).
Key Claims at a Glance
- The complaint asserts independent claim 1 and dependent claims 2-14 (Compl. ¶50).
- Independent Claim 1 requires:
- A method for making Rebaudioside X
- comprising a step of converting Rebaudioside D to Rebaudioside X
- using a UDP-glucosyltransferase,
- wherein the conversion of Rebaudioside D to Rebaudioside X is at least about 50% complete.
- The complaint reserves the right to assert other claims (Compl. ¶50).
U.S. Patent No. 10,485,257 - "Method for Making Steviol Glycosides"
- Issued: November 26, 2019 (Compl. ¶¶ 22-23).
The Invention Explained
- Problem Addressed: Similar to the ’273 Patent, this patent aims to provide efficient biocatalytic processes for preparing compositions of steviol glycosides for use as sweeteners (’257 Patent, col. 1:43-48).
- The Patented Solution: This invention describes a more general biocatalytic method for producing a target steviol glycoside. The process involves contacting a starting "steviol glycoside substrate" with a recombinant enzyme (UDP-glucosyltransferase) to add at least one glucose unit, thereby forming the desired target steviol glycoside, which is specified as Rebaudioside X in the asserted claim (’257 Patent, col. 1:50-67).
- Technical Importance: This method provides a flexible enzymatic pathway for synthesizing specific, high-purity steviol glycosides like Rebaudioside X, expanding the toolkit for creating next-generation, non-caloric sweeteners (Compl. ¶¶ 30-31).
Key Claims at a Glance
- The complaint asserts independent claim 1 and dependent claims 2-7 (Compl. ¶71).
- Independent Claim 1 requires:
- A method for adding at least one glucose unit to a steviol glycoside substrate to provide a target steviol glycoside,
- comprising contacting the steviol glycoside substrate with a recombinant biocatalyst protein enzyme comprising UDP-glucosyltransferase,
- wherein the target steviol glycoside is Rebaudioside X.
- The complaint reserves the right to assert other claims (Compl. ¶71).
III. The Accused Instrumentality
Product Identification
The accused instrumentality is the process used to manufacture sweeteners, including but not to "Bestevia" Rebaudioside M (Compl. ¶¶ 50, 71). The complaint alleges that Rebaudioside M and Rebaudioside X are synonyms (Compl. ¶26).
Functionality and Market Context
The complaint alleges that Defendants employ a proprietary "bioconversion" or "enzymatic conversion" process to create their Bestevia product (Compl. ¶37). This process is alleged to involve a series of glycosylation reactions catalyzed by UDP-glucosyltransferase (UGT) enzymes to convert precursor steviol glycosides, including Rebaudioside D, into the final product, Rebaudioside M (Compl. ¶¶ 45, 51). The complaint cites Defendants' own GRAS Notice submissions to the FDA as evidence for the technical steps of this process (Compl. ¶¶ 41-46). A key piece of visual evidence from these submissions is a diagram showing the production pathway. Figure 1 from the GRAS supplement depicts a schema for converting various steviol glycosides, including a direct pathway from Reb D to Reb M (Compl. ¶46, p. 9). The complaint notes the commercial importance of the product through its announced use by a "major global beverage company" (Compl. ¶36).
IV. Analysis of Infringement Allegations
'273 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method for making Rebaudioside X comprising | The accused process is used to make "Bestevia" Rebaudioside M, which is alleged to be synonymous with Rebaudioside X. | ¶51; ¶53 | col. 2:60-61 |
| a step of converting Rebaudioside D to Rebaudioside X | The accused process allegedly involves incubating Rebaudioside D to convert it to Rebaudioside M (X), as described in Defendants' licensed '604 patent. | ¶51; ¶53 | col. 3:19-22 |
| using a UDP-glucosyltransferase, | The accused process allegedly uses a UGT enzyme, as stated in Defendants' GRAS Notice and licensed '604 patent. | ¶51; ¶53 | col. 3:3-5 |
| wherein the conversion of Rebaudioside D to Rebaudioside X is at least about 50% complete. | The accused process allegedly achieves complete conversion, as inferred from language in the '604 patent and chromatograms in the GRAS Notice showing no remaining Reb D. | ¶52; ¶53 | col. 13:5-11 |
- Identified Points of Contention:
- Process Identity: A primary question is whether the process described in the '604 patent and GRAS notices, which forms the basis of the infringement allegations, is the actual process Defendants use to manufacture "Bestevia." The complaint makes this connection on "information and belief" (Compl. ¶39).
- Technical Proof: The complaint infers that the "at least about 50% complete" limitation is met because other documents describe the conversion as "complete" (Compl. ¶53). A point of contention may be whether this inference is sufficient proof, or if direct measurement of the accused process is required to establish the specific conversion rate claimed in the patent.
'257 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method for adding at least one glucose unit to a steviol glycoside substrate to provide a target steviol glycoside, | The accused process allegedly involves adding a glucose unit to various steviol glycoside substrates (e.g., Reb D) to produce Reb M (X), as shown in "Blue California's Schema for Steviol Glycosides Production" (Compl. ¶46). | ¶72; ¶73 | col. 1:50-53 |
| comprising contacting the steviol glycoside substrate with a recombinant biocatalyst protein enzyme comprising UDP-glucosyltransferase, | The accused process is alleged to use a UGT enzyme, as described in Defendants' GRAS Notice and licensed '604 patent. | ¶72; ¶73 | col. 1:53-56 |
| wherein the target steviol glycoside is Rebaudioside X. | The product of the accused process is "Bestevia" Rebaudioside M, which is alleged to be synonymous with the claimed target, Rebaudioside X. | ¶72; ¶73 | col. 2:28-29 |
- Identified Points of Contention:
- Substrate Scope: The claim recites a "steviol glycoside substrate." The complaint points to a schema from Defendants' GRAS supplement showing multiple potential substrates leading to Rebaudioside X (Compl. ¶¶ 46, 73). A question for the court may be whether the specific substrate(s) used in the accused process fall within the scope of the claims as practiced.
- Recombinant Biocatalyst: The claim requires a "recombinant biocatalyst protein." The complaint alleges the use of UGT enzymes from yeast strains (Compl. ¶41). A technical question will be what evidence confirms that the specific enzymes used in the accused process are "recombinant" as required by the claim.
V. Key Claim Terms for Construction
The Term: "UDP-glucosyltransferase" (Asserted in Claim 1 of '273 and '257 Patents)
Context and Importance: This term defines the core catalytic enzyme of the claimed methods. The scope of this term—whether it is limited to specific disclosed enzymes or covers a broader functional class—is central to determining whether the enzyme used in the accused process infringes.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: Both patents define the term functionally, stating it can be "any UDP-glucosyltransferase capable of adding at least one glucose unit to the steviol glycoside substrate" (’257 Patent, col. 2:30-34; ’273 Patent, col. 3:3-7). This language may support a broad, functional definition.
- Evidence for a Narrower Interpretation: The specifications also disclose specific enzyme examples, such as UGT76G1 and UGT91D2, and their use in preferred embodiments (’273 Patent, col. 12:5-7; ’257 Patent, col. 2:56-61). A defendant might argue these specific examples limit the claim scope to the disclosed enzymes or those with very similar structures.
The Term: "at least about 50% complete" (Asserted in Claim 1 of '273 Patent)
Context and Importance: This limitation sets a quantitative threshold for the efficiency of the claimed conversion process. Infringement of the ’273 patent hinges on whether the accused process meets this numerical requirement. Practitioners may focus on this term because its interpretation and the method of its measurement are likely to be disputed.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The use of the word "about" suggests the 50% figure is not a rigid, absolute floor. The patent does not define a specific range for "about," which could support an argument for some flexibility below the 50% mark.
- Evidence for a Narrower Interpretation: An example in the specification describes achieving an "80% conversion" as measured by HPLC (CAD), which establishes a method for measurement but does not test the lower boundary of the claim (’273 Patent, col. 29:32-41). A party could argue that "about 50%" requires a conversion rate that is functionally and numerically very close to 50%, and that the measurement must be performed using the method disclosed in the patent's own examples.
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement. It asserts inducement based on Defendants' marketing of "Bestevia" and working with customers to incorporate it into food and beverage products, allegedly with the specific intent to encourage infringement (Compl. ¶¶ 54, 74). Contributory infringement is alleged on the basis that "Bestevia" is a material part of the patented inventions, is specially made for an infringing use, and is not a staple article of commerce (Compl. ¶¶ 55, 75).
- Willful Infringement: The complaint alleges that infringement was willful based on both pre- and post-suit knowledge. Pre-suit knowledge of the ’273 Patent is alleged to be imputed to Defendants through their business partner and licensor, Conagen, which cited the ’273 Patent during the prosecution of its own related patent. The complaint further alleges that officers of Defendant SweeGen were also officers or inventors at Conagen, and thus knew of the patent (Compl. ¶¶ 62-64). Post-suit willfulness is alleged based on continued infringement after being served with the complaint (Compl. ¶69).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central evidentiary question will be one of process identity: Can Plaintiff prove that the process described in Defendants' public GRAS notices and licensed '604 patent—the primary evidence cited—is the same process Defendants actually use to manufacture the accused "Bestevia" product at a commercial scale?
- A key legal question for willfulness will be one of imputed knowledge: Can knowledge of the ’273 Patent, allegedly possessed by Defendants' licensor (Conagen) from its own patent prosecution activities, be legally imputed to the Defendants to establish the pre-suit knowledge required for a finding of willful infringement?
- A critical technical issue will be one of quantitative proof: For the ’273 Patent, does the accused process satisfy the "at least about 50% complete" conversion limitation, and can this be established by inference from documents describing "complete" conversion, or will direct evidence and a formal construction of the term "about" be required?