Tetraether type polar lipids increase after logarithmic growth phase of Methanobacterium thermoautotrophicum in compensation for the decrease of diether lipids

The ratios of tetraether to diether type lipids in the total lipid during cell growth in batch cultures of Methanobacterium thermoautotrophicumΔH (DSM 1053) were examined. The proportion of tetraether type lipids to the total lipid was about 80% during the log phase, and at the onset of the transient phase it began to rise up to about 93%. It was kept almost constant at that level throughout the stationary phase. The polar lipid composition changed with the age of the cell culture. The proportions of all the diether type polar lipids were lower and the levels of all tetraether type polar lipids were higher in the stationary phase than in the log phase. On the other hand, the composition of polar head groups, irrespective of the core lipids, was nearly constant in both growth phases measured so far despite the change in core lipid composition.