A new sesquarterpene, heptaprenylcycli-14E,18E-diene, was isolated from Mycobacterium chlorophenolicum cells grown up to the stationary phase. The absence of heptaprenylcycli-14Z,18E-diene indicates that only (E,E,E)-geranylgeranyl diphosphate may be utilized as an intermediate of sesquarterpene biosynthesis in the stationary phase, in contrast with the logarithmic growth phase in which both (E,E)-farnesyl diphosphate and (E,E,E)-geranylgeranyl diphosphate are used. Further, our findings suggest that the step-wise reduction of the polyprenyl group in sesquarterpene biosynthesis might proceed in a different order from that in chlorophyll biosynthesis. (C) 2012 Elsevier Ltd. All rights reserved.