[Kinetics of Pseudomonas fluorescens growth under different conditions of culturing]

The dynamics of Pseudomonas fluorescens VKM-1472 growth was studied under the conditions of batch and continuous cultivation, and the behaviour of the organism was investigated upon nutrition shifts and starvation. At D greater than 0.375 h-1, just as in the batch culture with a substrate excess, the strain realised excessive metabolism [15]: the yield in terms of the substrate fell down (38% for the batch culture and 40% for the continuous culture), the titre of viable cells decreased to a considerable extent, and maintenance expenditures increased (3 times for qgluc and 7.5 times for qO2). When the culture was incubated under the oligotrophous conditions, the biomass yield decreased fourfold within 8 days and the titre of viable cells dropped down twofold within the same period of time. However, the organism was still capable of oxidising a wide range of substrates (17 substrates were studied). As soon as a substrate was added, it was oxidised at a high rate and changes in the macromolecular composition were characteristic of an "up-jump" in the growth rate [11]. It is possible that the growth and behaviour of this organism are associated with its ecological niche occupied in natural systems.