Court Issues Mixed Claim Construction Ruling in Ethanol Processing Patent Case


A previous post reported on the consolidation of a number of patent infringement suits brought by GreenShift and its New York subsidiary, GS Cleantech, against a host of ethanol producers across the midwestern United States.

GreenShift has accused the defendants of infringing U.S. Patent No. 7,601,858 (’858 Patent), entitled “Method of processing ethanol byproducts and related subsystems.”

The ’858 Patent is directed to methods of recovering oil from byproducts of ethanol production using the process of dry milling, which creates a waste stream comprised of byproducts called whole stillage.

According to the ’858 Patent, whole stillage contains valuable oil but prior processes for recovering this oil have been expensive or inefficient.

GreenShift’s patented method includes mechanically separating the whole stillage into distillers wet grains and thin stillage and then running the thin stillage into an evaporator to form a concentrated byproduct, or syrup. The syrup is fed through a second centrifuge, which separates usable corn oil from the syrup.

In September 2010 the Judicial Panel on Multidistrict Litigation granted GreenShift’s motion to consolidate the 11 actions in the Southern District of Indiana.

Recently, the court issued a “Markman” decision (GS-Markman-Order), a claim construction order that provides the court’s interpretations of key disputed terms of the patent claims.

There were several terms of the ’858 Patent claims at issue, the most important of which were ”concentrated byproduct”, “concentrate”, “thin stillage concentrate” and ”concentrated thin stillage” (collectively construed by the court as “the Concentrate Terms”), as well as ”mechanically processing”.

In one instance, the court adopted the defendants’ narrower proposed construction. In the other, it went with GreenShift’s broader proposed definition.

The question in interpreting the Concentrate Terms was essentially what the byproduct or concentrated substance is. GreenShift argued that it is any product consisting of water, oil and solids, while the defendants contended it should be limited to a syrup.

The court agreed with the defendants and construed the Concentrate Terms to mean “syrup containing water, oil, and solids resulting from the concentrating or evaporating process.”

According to the court, this interpretation “naturally aligns” the claim language with the description in the ’858 Patent, which uses the terms “concentrate” and “syrup” interchangeably to identify the composition described by the Concentrate Terms.

The court construed the term “mechanically processing” to mean “to subject to a mechanical device (or devices) to effect a particular result.” Despite defendants’ contention that the term means “processing with a centrifuge,” the court agreed with GreenShift that the plain meaning of the term requires a broader construction.

As discussed before in this space, the claim construction phase of patent litigation is extemely important, often leading to settlement or dismissal on summary judgment.

With what appears to be a mixed ruling leaving no clear winner, it will be interesting to see what happens next in this major biofuels litigation.

Eric Lane is a patent attorney at Luce, Forward, Hamilton & Scripps in San Diego and the author of Green Patent Blog. Mr. Lane can be reached at

About Author

Walter’s contributions to CleanTechies over the past 4 years have been instrumental in growing the publications social media channels via his ongoing editorial and data driven strategies. He is the founder and managing director of Sunflower Tax, a renewable energy tax and finance consultancy based in San Diego, California. Active in the San Diego clean technology community, participating in events sponsored by CleanTech San Diego, EcoTopics, and Cleantech Open San Diego, Walter has also been a presenter at numerous California Center for Sustainability (CCSE) programs. He currently serves as an adjunct professor at the University of San Diego School of Law where he teaches a course on energy taxation and policy.

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