SEMI-CONTINUOUS-FLOW CULTURES WITH MARINE SEDIMENT SUSPENSIONS CONTAINING NONPOLAR CARBON-SOURCES - CULTURE CONTROL BY A PNEUMATIC SEDIMENTSUSPENSION DOSAGE SYSTEM

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 (aq ueous phase) containing the sediment (solid-phase) and the hydrocarbon (non-polar phase). If pumps were to be used for supplying this suspen sion to the fermenter, separation of the different phases (solid, aque ous, non-polar) could occur. We developed a technique with which dosag e can be carried out without pumps by using glass tubes with a calibra ted tilling volume. A computer program is used for dosage control and documentation of the suspension flow-rate. Steady state continuous cul tivation of the bacterial population of mud Rat sediment from the Germ an North Sea coast could be maintained for more than eight weeks. (C) 1997 Elsevier Science B.V.