THE FORMATION OF OXYTETRACYCLINE IN A DATE-COAT MEDIUM

Chemical analyses of Saudi cultivars of dates revealed that the fleshy date-coats contain large amounts of reducing sugars, especially glucose, fructose and sucrose. The date-coats also contain protein, lipid, fibre, mineral elements and some vitamins. The percentage of total lipid and protein of date-seeds was higher than of date-coats. In contrast, the percentage of ash in date-seeds was lower than in date-coats. Sixteen amino acids were found in both date-seed and date-coat hydrolysate. Ca, Mg, Sr, Si, Al, Ni, Fe, Zn, Cu, Cr, Pb, Mn, P, Li, Na, and K were present in both date-seeds and date-coats. Different oxytetracycline producers were investigated for their efficiencies in forming the antibiotic; Streptomyces rimosus NRRL B-2234 was found to be the most efficient. The fermentation production of oxytetracycline is distinguished by two stages. In the first stage, a drop in pH and formation of microbial constituents occurs, and in this phase little oxytetracycline is produced; in the second stage, the organism produces more antibiotics. Glucose at 30 g/litre was the best carbon source, while urea at 2.0 g/litre was the best organic nitrogen source with KH2PO4 at 1.0 g/litre. Tests of the different date-coat extracts for the fermentative formation of oxytetracycline, showed that date-coat extracts were more efficient than glucose when used as a carbon source.