Detection and Expression of Biosynthetic Genes in Actinobacteria ...

BERVANAKIS, G.Chapter 1: INTRODUCTIONproduced by S. cinnamonensis and tobramycin produced by S. cremeus (Stark et al.,1968; Motkova et al., 1982).The effects of certain trace elements are not exerted unless they are used incombinations (Weinberg, 1989). An example is the use of Zn and Fe inchloramphenicol production where the incorporation of these combined minerals leadto a five fold increase in production of the metabolite as compared to Zn or Fe usedindependently (Table 14). Calcium (Ca 2+ ) and copper (Cu 2+ ) have also been shown tohave a synergistic effect leading to an increase in vancomycin production inAmycolatopsis orientalis. The high productivity was shown to be due to Ca 2+ alteringcell permeability leading to increase in intracellular vancomycin being egressed andCu 2+ increasing the activity of biosynthetic enzymes in the cells (Jung et al., 2002).Table 14. The effects of iron and zinc on the production of chloramphenicol byStreptomyces venezuelae (adapted from Gallicchio & Gottlieb, 1958).Culture mediumGlycerol-lactate plus:Mycelial dry weight(mg/ml)Chlorophenicol(μg/ml)Iron Zinc(100 μM) (100 μM)0 01.132