Semi-continuous-flow cultures with marine sediment suspensions containing non-polar carbon sources—culture control by a pneumatic sediment suspension dosage system

Abstract A system for the continuous cultivation of microorganisms in sediment/seawater suspensions containing hydrocarbon as carbon source has been developed. The culture vessels are supplied with a liquid nutrient (aqueous phase) containing the sediment (solid-phase) and the hydrocarbon (non-polar phase). If pumps were to be used for supplying this suspension to the fermenter, separation of the different phases (solid, aqueous, non-polar) could occur. We developed a technique with which dosage can be carried out without pumps by using glass tubes with a calibrated filling volume. A computer program is used for dosage control and documentation of the suspension flow-rate. Steady state continuous cultivation of the bacterial population of mud flat sediment from the German North Sea coast could be maintained for more than eight weeks.