Abstract
The attainment in Bradyrhizobium japonicum 5019 cultures of very high cell concentrations was studied by a closed batch system, where all the medium components were incorporated at the beginning of the process. The studies performed allow the establishment of the process conditions that, operating in a stirring fermenter at 400 rev min-1 and employing an aeration rate of 0.5 11-1 min-1 (oxygen absorption rate 513 ml O 2 I-1 h-1), make possible the attainment of a cell concentration of the order of 5 x 1010 viable cells ml-1 in 75 h, using a basic medium containing yeast extract, glycerol and salts.
