Via Rule 11 of the Federal Rules of Civil Procedure all actions brought in federal court have a pre-filing investigation requirement. Rule 11 demands that before any claim is asserted, the party asserting the claim must have performed an "inquiry reasonable under the circumstances" as to the legal and factual merits of the claim. Fed. R. Civ. P. 11(b).
One notes the response of Paul Beckwith of Butamax to Gevo's infringement assertion of 13 Sept 2011, as mentioned in BiofuelsDigest:
“When Butamax makes isobutanol, we do not use the technology claimed in the Gevo patents. We are so confident about this, that we offered Gevo an opportunity to independently verify that Butamax does not infringe either of these patents. Ignoring both our offer to verify and the facts, Gevo instead filed its lawsuit.”
link to Biofuels Digest
link to IPBiz on Rule 11
Gevo bites back in isobutanol biofuel area; goes after Butamax with US 8,017,375