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Anovel antibiotic, GE2270A, was isolated from the fermentation broth of a strain of Planobispora rosea. The product was found to inhibit bacterial protein synthesis. Structural characteristics showed similarities between GE2270 A and thiazolyl peptides such as micrococcin which is known to inhibit protein synthesis by acting directly on the ribosome. Despite this similarity GE2270A showed functional analogy to kirromycin-like antibiotics and pulvomycin, as its molecular target was found to be elongation factor Tu (EF-Tu). GE2270A is active against Gram-positive microorganism and anaerobes and differs from the other EF-Tu inhibitors in its spectrum of antimicrobial activity. 693 GE2270A, a novel peptide antibiotic, emerged from a screening program designed to detect inhibitors of protein synthesis. The present paper deals with the discovery, isolation, initial physico-chemical and biological characterization of this antibiotic. Materials and Methods Cultural and Growth Characteristics of the Producing Strain Colonial and morphological characters were determined with standard methods1'2*. Color determination was madeaccording to Maerz and Paul3). Growthon sole sources of carbon was determined after incubation at 28°C for 2 weeks1*. Chemotaxonomic Characteristics of the Producing Strain Freeze-dried biomass was examined to determine the major chemotaxonomiccharacteristics. Cell wall diamino acids were determined by TLCby a modification of the method of Becker et a/.4)5). Wholecell sugars were hydrolyzed, reduced and derivatized. The resultant alditol acetates were analyzed by GC6). Fatty acid methyl esters were similarly analyzed by GC7). Menaquinones and polar lipids were extracted and analyzed by HPLCand 2D TLC, respectively8*. Fermentation of the Producing Strain A 500-ml Erlenmeyer flask containing 100 ml of seed medium (Pdlypeptone 0.5%, yeast extract 0.3%, beef extract 0.2%, soybean meal 0.2%, starch 2%, calcium carbonate 1%, pH 7.0) was inoculated from an oatmeal slant of the producing strain. After incubation at 28°C for 96 hours on a rotary shaker (200 rpm), the biomass was transferred to a 10-liter jar fermenter containing 4 liters of the seed medium. This culture was grown for 72 hours at 28°C with 2 liters/minute air flow and stirring at 900rpm, prior to inoculating a jar fermenter containing 50 liters of production medium(starch 2%, peptone 0.25%,

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The producer strain of the new antibiotic, lipiarmycin, is described. The colony morphology, the presence of globose sporangia bearing motile spores, the absence of aerial mycelium and the presence of meso-DAP in cell wall, ascribe this strain to the genus Actinoplanes. The pigmentation and morphological characteristics together with the cultural and physiological features distinguish this strain from all the described Actinoplanes species. It is considered to be a new species for which the name Actinoplanes deccanensis nov. sp. is proposed. Lipiarmycin is produced in an organic complex medium containg NaCI. Production occurs at the end of trophophase and continues, though at decreasing rate, during idiophase.

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