Process-Claim “Result” Parameters and Appellate Restraint on Obviousness: “Lipid contains <5% organic solvent” Means the Separated Product

1. Introduction

DSM IP Assets BV & Anor (“DSM”) and Mara cross-appealed from aspects of Mellor J’s order following a nine-day patent trial. DSM alleged infringement of three patents relating to microbial oils (notably omega‑3 DHA) and their production/extraction processes; Mara denied infringement and counterclaimed for revocation.

At first instance: EP155 was held valid (infringement admitted if valid); EP740 invalid; EP801 invalid for obviousness (though would have been infringed by some Mara processes if valid). On appeal, Mara challenged the finding that EP155 was not obvious; DSM challenged the finding that EP801 was obvious and (contingently) aspects of infringement.

The Court of Appeal dismissed both appeals. Two themes dominate the judgment: (i) the high threshold for overturning a trial judge’s evaluative obviousness conclusion; and (ii) a claim-construction point of practical drafting significance—where a process claim states “wherein the lipid contains less than 5% by weight of an organic solvent”, that limitation was construed as a property of the lipid obtained/separated, not a constraint applying “throughout” the process.

2. Summary of the Judgment

  • EP155 (Mara’s appeal): The Court upheld the trial judge’s conclusion that claim 1 was not obvious over “Bijl”. The judge’s reasons—particularly the concern that Mara’s case effectively used “Bijl” merely as a “hook” to pick up enzymatic lysis and was infected by hindsight—disclosed no error of law or principle.
  • EP801 (DSM’s appeal): The Court upheld the trial judge’s construction that “the lipid contains less than 5% by weight of an organic solvent” refers to the lipid resulting from the process, and not to the lipid “during” intermediate process stages. On that construction, DSM’s obviousness challenge fell away; in any event, the Court agreed the judge had not erred in holding EP801 obvious even on DSM’s preferred construction.
  • Contingent issues: DSM’s further claim-construction/infringement point regarding “pH 8 or above” was not reached because it depended on DSM succeeding on earlier grounds.

3. Analysis

3.1 Precedents Cited (and How They Shaped the Outcome)

(a) Avoiding hindsight and “step-by-step” reconstructions

The Court reiterated the classic warning in Technograph Printed Circuits Ltd v Mills & Rockley (Electronics) Ltd [1972] RPC 346. The danger is reconstructing an invention a posteriori by assembling seemingly routine steps once the successful endpoint is known. This caution materially informed the EP155 analysis: the first-instance judge’s conclusion that Mara’s route from “Bijl” to claim 1 looked like a hindsight-driven selection of enzymatic lysis (divorced from what was genuinely “new” in Bijl) was treated as a legitimate evaluative conclusion.

(b) Obviousness over common general knowledge alone—caution

The Court referenced the need for care before finding obviousness over CGK alone, citing Ratiopharm GMBH v NAPP Pharmaceutical Holdings Ltd [2008] EWHC 3070 (Pat), [2009] RPC 11. This supported the judge’s framing that Mara’s EP155 attack, properly analysed, collapsed towards “CGK enzymatic lysis” rather than a true “Bijl-driven” obviousness case—making the absence of a persuasive, non-hindsight motivation to pursue enzymatic lysis especially significant.

(c) Appellate restraint on multi-factorial evaluative judgments

On the standard of review, the Court applied Actavis Group PTC EHF v ICOS Corp [2019] UKSC 15 and reinforced it with Lifestyle Equities CV v Amazon UK Services Ltd [2024] UKSC 8 and Iconix Luxembourg Holdings SARL v Dream Pairs Europe Inc [2025] UKSC 25. These authorities underpin that obviousness is a multi-factorial evaluation; the Court of Appeal should not interfere absent an error of law/principle. This was decisive for Mara’s EP155 appeal: even if Mara could argue for a different evaluative outcome, it could not show the judge had gone wrong in principle.

(d) Purposive claim construction in context (Art. 69 EPC)

For EP801, the Court anchored construction in Virgin Atlantic Airways v Premium Aircraft Interiors [2009] EWCA Civ 1062, [2010] RPC 8, with its Art.69 EPC purposive, contextual approach—balanced by the reminder that “purpose is not conclusive” and that the claim language delineates the patentee’s territory. The Court also noted the post-Actavis UK Ltd v Eli Lilly & Co [2017] UKSC 48 landscape (though the key quotation was used primarily for general construction principles).

3.2 Legal Reasoning

(A) EP155: Why “Bijl” did not make enzymatic protease lysis of Schizochytrium obvious

Claim 1 of EP155 required (i) Schizochytrium biomass; (ii) contacting with an enzyme; (iii) recovering lipid; where the enzyme treatment comprises a protease. Mara’s attack relied on “Bijl”, which broadly described solvent-free oil recovery after lysis (including enzymatic lysis and mentioning proteases).

The trial judge had found “Bijl” to be a “strange document” and identified practical scepticism a skilled team would have had (notably: emulsion formation and whether centrifugation alone could separate oil effectively after mechanical lysis). Against that background, the judge’s core evaluative findings—upheld on appeal—were:

  • What “Bijl” added (solventless centrifugation separation) was not the driver of Mara’s case; Mara’s obviousness route effectively extracted only the generic idea of enzymatic lysis, which was CGK.
  • No persuasive motivation was shown for why “this mention” of enzymatic lysis in “Bijl” would trigger the skilled team to pursue it (especially in the short window before EP155’s priority date), when enzymatic lysis had been “around for some years”.
  • The emulsion argument (“enzymatic lysis produces a gentler, more breakable emulsion”) lacked evidential footing as a skilled-reader inference from “Bijl” (as opposed to hindsight). The Court of Appeal carefully analysed the cited cross-examination: it did not establish that the skilled reader would follow Mara’s posited chain of reasoning; nor was it put in that form to the expert.

Critically, the Court of Appeal treated these as classic evaluative findings of fact and expert evidence weight. Applying the Actavis Group PTC EHF v ICOS Corp appellate restraint, it declined to re-run the obviousness assessment.

(B) EP801: The “<5% organic solvent” clause constrains the separated lipid, not intermediate compositions

DSM’s primary route to reversing the EP801 obviousness finding was to re-interpret claim 1 so that “wherein the lipid contains less than 5% by weight of an organic solvent” applied throughout the process (including when lipid is still within the lysed/demulsified emulsion). The Court rejected that construction, for essentially linguistic and functional reasons:

  • Anaphoric reference in the claim: “the lipid” was read as referring back to “a lipid” (the subject of the overall process and step (d) “separating a lipid”), i.e. the lipid obtained by separation.
  • Workability and sense: imposing a “lipid contains <5% solvent” requirement at stages where lipid is part of a complex emulsion was said to be “very odd”; by contrast, applying the limitation to the separated lipid product is intelligible.
  • Drafting contrast within the patent: the specification elsewhere used composition-based concentrations (e.g. lipid % in broth/lysate), showing the drafter knew how to constrain intermediate compositions if that was intended.

The Court also made a broader doctrinal point: a process claim can legitimately be defined in part by its result. That neutralised DSM’s argument that, because only process claims were asserted, the “<5%” clause must regulate process conditions rather than an endpoint property.

(C) EP801 obviousness over “Kobzeff” (even on DSM’s construction)

Although not strictly necessary given the construction ruling, the Court addressed DSM’s subsidiary complaints. It found no error in the judge’s acceptance (based on CGK and the evidence) that salt and/or heating could be tried as obvious de-emulsification techniques without needing a polar solvent, and that a reasonable expectation of success was implicit given the CGK that bench testing would identify which demulsification combinations worked for a given emulsion strength.

3.3 Impact

  • Claim drafting and litigation strategy (process/result parameters): The EP801 ruling is a cautionary illustration that an apparently “process-centric” limitation (organic solvent %) may be construed as a product/result requirement if the claim language naturally reads that way. Parties seeking “throughout the process” constraints must draft expressly (e.g. by limiting solvent content of “the lysed cell composition” or “the demulsified cell composition”).
  • Obviousness: evidential discipline and motivation: The EP155 outcome emphasises that identifying each step as “doable” is not enough; the fact-finder will ask what motivates the skilled team to pursue the specific combination without hindsight, especially where the prior art is viewed as unreliable, speculative, or “odd”.
  • Appeals: deference is real: The Court’s reliance on Actavis Group PTC EHF v ICOS Corp (and later UKSC authorities) signals that patent obviousness appeals must be framed as true errors of principle, not invitations to re-weigh expert evidence or re-prefer an alternative evaluative narrative.

4. Complex Concepts Simplified

  • Common general knowledge (CGK): the background technical knowledge and standard practices the “skilled team” would be assumed to know at the priority date, without needing to look anything up.
  • Skilled person/team: a legal construct—here, a team spanning upstream (microbiology/fermentation) and downstream (extraction/separation engineering) expertise.
  • Obviousness: whether the invention would have been obvious to the skilled team in light of CGK and prior art, without inventiveness. The Court warned against hindsight reconstruction (Technograph Printed Circuits Ltd v Mills & Rockley (Electronics) Ltd).
  • Emulsion / demulsification: oil and water can form stable dispersions after cell lysis; “demulsifying” means making the system separate into phases (oil phase vs aqueous phase) using techniques like salt, heat, stirring, solvents, and centrifugation.
  • Purposive construction (Art.69 EPC): interpreting claim words in their technical context to capture what the patentee was using the language to mean, but still respecting the actual language chosen (Virgin Atlantic Airways v Premium Aircraft Interiors).
  • Respondent’s notice: a mechanism allowing a respondent to argue that the decision should be upheld for different reasons (here, Mara’s alternative obviousness case over “Hendrik” was contingent and fell away).

5. Conclusion

The Court of Appeal’s dismissal of both appeals leaves two practical lessons. First, obviousness findings are highly resistant on appeal: without a demonstrable legal/principled error, the appellate court will not re-litigate a trial judge’s evaluative assessment of expert evidence and motivation, particularly where hindsight is in issue (Actavis Group PTC EHF v ICOS Corp; Technograph Printed Circuits Ltd v Mills & Rockley (Electronics) Ltd). Second, in claim construction, result-defining parameters in process claims will be taken seriously as endpoint properties when the claim’s grammar and context point that way—here, “the lipid contains less than 5% by weight of an organic solvent” meant the lipid after separation, not lipid at every intermediate stage.