The invention relates to a method for producing 2,3-butanediol using improved strains of Raoultella planticola, and to novel mutant strains obtained by random mutagenesis from the bacterial species Raoultella planticola CECT843, that can be used in the industrial production of 2,3-butanediol from glycerol. The oxo-groups, in combination with portions of the perylene core, form a quinoid system of bonds. In particular, the device is arranged to control the ring signal voltage so that the ring signal voltage is reduced if the voltage on the A or B line exceeds the reference voltage. At least one recess is formed into the outer surface of the cover.