The complete carotenoid composition of the thermophilic green sulfur bacterium Chlorobium tepidum strain TNO was determined by spectroscopic methods. Major carotenoids were four kinds of carotenes: γ-carotene, chlorobactene, and their 1',2'-dihydro derivatives (1',2'-dihydro-γ-carotene and 1',2'-dihydrochlorobactene). In lesser amounts, hydroxyl γ-carotene, hydroxyl chlorobactene, and their glucoside fatty acid esters were found. The only esterified fatty acid present was laurate, and OH-chlorobactene glucoside laurate is a novel carotenoid. In other strains of C. tepidum, the same carotenoids were found, but the composition varied from strain to strain. The overall pigment composition in cells of strain TNO was 4 mol carotenoids and 40 mol bacteriochlorophyll c per mol bacteriochlorophyll a. The effects of nicotine on carotenoid biosynthesis in C. tepidum differed from those inthe thermophilic green nonsulfur bacterium Chloroflexus aurantiacus.
ASJC Scopus subject areas
- Molecular Biology