“L-glutamate Production Strain and Method of Manufacturing L-glutamate”


This case concerns an appeal to the Intellectual Property High Court (IP High Court) of Japan, with regards to a decision rendered by the Japanese Patent Office (JPO) of maintaining a patent valid. The IP High Court upheld the JPO’s decision.

Main Issue:

Whether claim 11 complies with the support requirement based on the specification in regards to a 19-type mutant Corynebacterium.

Summary of Conclusion:

It was established that the patent addresses a technical problem related to enhancing L-glutamate production in the manufacture of L-glutamate using Corynebacterium, and that claim 11 includes steps for enhancing production not only under inducing conditions but also under non-inducing conditions. The court considered that example 10 of the specification discloses that the production of ATCC13869-19 (a strain into which a 19-type mutation has been introduced under inducing conditions) is enhanced compared to the wild-type strain. The court held that one of ordinary skill in the art could recognize from this disclosure that glutamate production had been enhanced under inducing conditions for a 19-type mutation.
Additionally, the court held that one of ordinary skill in the art would recognize from example 8 which describes a test performed in relation to enhancement in production of a 19-type mutant strain under non-inducing conditions, that the problem to be solved could be overcome under non-inducing conditions for a 19-type mutation.
Consequently, the court concluded that claim 11 satisfies the support requirement in regards to a 19-type mutation.


The plaintiffs asserted that the difference in production of glutamate with a wild-type strain and with a 19-type mutation disclosed in example 8 merely falls within the margin of error, and that therefore one of ordinary skill in the art could not recognize from example 8 that the production of the glutamate is enhanced. Nevertheless, the IP High Court dismissed the plaintiffs’ arguments, taking into consideration blank test values and results of the wild-type strain glutamate yield in the other examples, holding that the difference in the glutamate yield for the wild-type strain and 19-type mutation in example 8, which differs from the values of the other examples, could not be based on error.