A new bacteriochlorophyll has been isolated by thin layer chromatography from all strains of the brown-colored Chlorobiaceae Chlorobium phaeobacteroides and Chlorobium phaeovibriodes. The new bacteriochlorophylle--like the bacteriochlorophylls c and d--represents the major amounts of bacteriochlorophyll a. Bacteriochlorophyll e can be differentiated from the bacteriochlorophylls c and d by its absorption maxima in aceton and its different Rf-value in the thin layer chromatogram. The structure of the new bacteriochlorophyll e has been elucidated on the basis of mass spectra, 1H-and 13C-NMR-spectra, the UV/VIS-spectrum as well as IR-, ORD-, and CD-spectra. The new bacteriochlorophyll has the same relationship to bacteriochlorophyll c as chlorophyll b from green plants to chlorophyll a; therefore, bacteriochlorophyll e represents the first formyl-substituted chlorophyll from bacteria. Similar to the bacteriochlorophylls c and d, the new bacteriochlorophyll e consists of a mixture of at least three homologues which differ from each other by different substituents on the pyrrol rings II and III.

Fermentations were performed in 70-liter fermentors (Giovanola, Manthey, Switzerland) equipped with a circulating pump stirrer system ("intensor system"). Antifoam Lb 625 (Brenntag, Miilheim/ Ruhr) was added to the medium in a concentration of 0.03 %. To start the culture, 63 liters of medium were inoculated with 7 liters of shake culture broth in mid-log phase. The fermentor was maintained at 30°C, and stirred at 500 r.p.m. The aeration rate was 0.1 v/vm for the first 13 hours, and 0.17 v/vm for the following 17 hours. The pH was held constant at 7.5 with acetic acid. Within 8 hours after

The myxobacterium, Myxococcus virescens strain Mx v48 produced a family of at least 12 closely related antibiotics, the myxovirescins***.At a concentration of 1 to 5 iig/ml, the main component, myxovirescin A, was bactericidal for many Gram-negative bacteria, in particular enterobacteria, and at 20 to 50 Egg/ml it also inhibited some pseudomonads and Grampositive bacteria. The antibiotics seem to interfere with cell wall synthesis. The molecular formula of myxovirescin A was C35H61NO3. It is a new antibiotic. Batch cultures of 100 ml were incubated in 250-m1 Erlenmeyer flasks at 32°C on a rotary shaker at 160 cycles per minute. Under these conditions, Mx v48 grew as a cell suspension with a generation time of 5 to 6 hours. The antibiotic activity appeared in the culture supernatant. As the yield was very low (about 0.2 leg/ml), the antibiotic could be demonstrated by the paper disk method only after concentrating the broth 50: 1. No antibiotic could be extracted from the cells with acetone or methanol.The activity was excreted only during exponential growth and disappeared again before the culture entered the stationary phase. Growth of the producing organism was inhibited by its own antibiotic by 50% at a concentration of 0.25 µg/ml. We therefore isolated mutants that were resistant against the antibiotic. These, as all other mutants isolated in the course of this study, were obtained by treat ment with N-methyl-N'-nitro-N-nitrosoguanidine. One of the Mutants, Mx v48-M3, was resistant against 30 to 40 pg/ml of the antibiotic. It still produced only 0.2 fig/ml, but production was now at the end of the growth phase, and the antibiotic remained stable during the following stationary phase.We then looked for mutants with higher yields. Mutagenized cultures of Mx v48-M3 were plated, and after 10 days the developing colonies were covered with a thin layer of agar containing cells of Escherichia

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