Microthrix parvicella, a Filamentous Bacterium from Activated Sludge: Growth on Tween 80 as Carbon and Energy Source

Department of Microbiology, Agricultural University, 6703 CT Wageningen, The Netherlands ABSTRACT Microthrix parvicella , cultivated in a medium with Tween 80 and Casamino acids, utilized only the oleic acid moiety of Tween 80 as carbon and energy source. The cell yield from Tween 80 was about 0.32 g dry weight of cells per g of Tween 80 consumed. As only the oleic acid moiety of Tween 80 was utilized, the cell yield from oleic acid was 1.3 g dry weight of cells per g oleic acid consumed. The amount of carbon produced as CO 2 was less than 30% of the oleic acid-carbon and this low value was in agreement with the high cell yield. In batch culture M. parvicella stored large amounts of lipid material during the early growth phase. The fatty acids of the lipid globules were similar to the fatty acids supplied as carbon source. The percentage composition of the biomass changed to give C/N percentage ratios of about 15 during the early growth phase due to the high concentration of internal lipids and the low concentration of protein. The growth rate in batch culture was about 0.016 h -1 but was affected by the concentration of Casamino acids in the medium. Present address: Gist Brocades NV, PO Box 1, Delft, The Netherlands.