Main request: "1. A method of solubilizing protease crystals and/or protease precipitate in a fermentation broth comprising
a) diluting the fermentation broth 100-2000% (w/w);
b) adding a divalent salt; and
c) adjusting the pH value of the fermentation broth to
a pH value below 5.5,
wherein the protease is a subtilisin."
The claimed method comprises as step a) diluting a fermentation broth that comprises subtilisin crystals and/or subtilisin precipitate.
A technical contribution to the art requires that the claimed invention can be realised by the skilled person at the effective date of the patent. In the present case, realisation of the method requires that a fermentation broth comprising subtilisin crystals or subtilisin precipitate be available to the skilled person.
Neither the patent nor the state of the art cited therein provide any guidance for the skilled person with respect to the technical measures to be applied in the fermentation process of subtilisin proteases to achieve such high yields that subtilisin crystallises spontaneously in the fermentation broth during fermentation.
With respect to the respondent's (the patentee) assertion that the fermentation yield could be raised above the solubility limit by optimising the production microorganism using routine techniques that belonged to the common general knowledge of the skilled person, the board notes that no corroborating evidence was provided by the respondent in this respect.
The board concurs with the appellant (the opponent) that there exists no common general knowledge on how to obtain the high yield of subtilisin needed to achieve a fermentation broth with crystals.
The board concludes from the above considerations that the appellant has discharged their burden of proof and that the respondent has not established that the embodiment under consideration was indeed workable for the skilled person without undue burden using common general knowledge at the effective date of the patent.
The claimed invention is not disclosed in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art as required by Article 83 EPC in the main request nor in any one of the auxiliary requests 1 to 9 for the same reasons.