Bacterial growth in space flight: logistic growth curve parameters for Escherichia coli and Bacillus subtilis

Previous investigations have reported that bacterial suspension cultures gr ow to higher stationary concentrations in space flight than on Earth; howev er, none of these investigations included extensive ground controls under v aried inertial conditions. This study includes extensive controls and cell- growth data taken at several times during lag phase, log phase, and station ary phase of Escherichia coli and Bacillus subtilis. The Marquardt-Levenber g, least-squares fitting algorithm was used to calculate kinetic growth par ameters from the logistic bacterial growth equations for space-flight and c ontrol growth curves. Space-flight cultures grew to higher stationary-phase concentrations and had shorter lag-phase durations. Also, evidence was fou nd for increased exponential growth rate in space.