Studies on production of gentamicin from Micromonosporas purpurea using crude vegetable oils
ABSTRACT Crude vegetable oils and natural nitrogen sources were investigated to evaluate their potential as energy sources for the efficient production of gentamicin from Micromonosporas purpurea. Of the various crude vegetable oils, soybean oil was found to be the most suitable carbon source for efficient gentamicin production. An initial concentration of 40 g/l gave the highest gentamicin concentration and lipase activity, at 0.75 g/l and 298.1 U/ml, respectively. However, with more than 60 g/l oil, both of these values deceased. When 0.4 g/l of linoleic acid was added to the culture broth, the maximum gentamicin concentration was 0.82 g/l, which was about 3.0-fold higher than that obtained without the addition of linoleic acid. Soybean meal and corn steep liquor (CSL) appeared to be the most important nitrogen sources for the production of gentamicin. Especially, with a mixture of 15 g/l soybean meal and 15 g/l CSL, the gentamicin production was higher than with the use of a sole nitrogen source. The oil consumption increased with increasing agitation rate of the jar fermentor. However, the maximum gentamicin concentration of 1.45 g/l was achieved after 5 days in the culture agitated at 400 rpm.Using these basic results, fed-batch cultures were performed for 8 days in a jar fermentor. When soybean oil was used, the extracellular protease activity was 920.5 U/ml, which was 3.6-fold higher than that of the glucose medium. The maximum gentamicin concentration was 3.5 g/l, which was about 4.9-fold higher than that of the glucose medium. The product yield of the consumed soybean oil was about 12.8-fold higher than that of the glucose medium.
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ABSTRACT: Computer-generated holograms (diffractive elements) can be used for shaping submillimeter-wave beams, e.g., for producing a plane wave in a compact space. An amplitude hologram has proved to be a feasible alternative as a focusing element in a compact antenna test range (CATR) at submm-wavelengths. In a recent study, we have designed and constructed a compact antenna test range for 322 GHz and measured the ADMIRALS representative test object, which is a 1.5-meter offset paraboloid antenna. In another study, the feasibility of a phase hologram based RCS (radar cross section) range has been verified with simple test objects.Physics and Engineering of Microwaves, Millimeter, and Submillimeter Waves, 2004. MSMW 04. The Fifth International Kharkov Symposium on; 07/2004
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ABSTRACT: Gentamicin is an aminoglycoside antibiotic produced by various species of the genus Micromonospora and has received much attention in the recent years as a broad-spectrum antibiotic for treatment of various infections. It exists as a complex of closely related aminoglycoside structures and the clinically significant one is the gentamicin C complex. This review article focuses attention on the present status of knowledge and the main advancements achieved in the last few decades on the subject of gentamicin with regard to its production, biosynthetic pathway, mode of action, and uses. The various nutritional and environmental parameters affecting gentamicin production and the factors affecting the release of bound gentamicin are discussed. Further, strain improvement using UV and/or chemical mutagenesis can be applied to augment the efficiency of the producer strain and a number of case studies are presented. Different detection and quantitative methods for gentamicin estimation and the mode of action of gentamicin are discussed in detail. This antibiotic finds extensive use in combination chemotherapy and as a drug for different delivery agents for treatment of osteomyelitis and other recent applications in gene therapy.Critical Reviews in Biotechnology 02/2008; 28(3):173-212. · 5.10 Impact Factor