SHOCK INDUCED JADOMYCIN PRODUCTION FROM STREPTOMYCES VENEZUELAE ISP5230 VS1099
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The production of jadomycin by Streptomyces venezuelae was carried out by applying various environmental stress conditions on the culture in nutrient deprived, amino acid rich MSM production media. The effects of culture transfer time (18, 21 and 24 h) from the growth media to the production media, heat shock at different temperatures (35, 40, 45 and 50°C) and exposure times (0.5 and 1 h), alcohol shock using ethanol and methanol at various concentrations (3.0, 4.5, 6.0 and 7.5 % v/v), multiple shocking by 3 % v/v ethanol at various times [once (0 h), twice (0, 3 h) and three times (0, 3 and 6 h)] and ethanol shock with various concentrations (3.0, 4.5 and 6.0 % v/v) and varying nitrogen concentrations (45, 60 and 75 mM) in the media on the growth and activity of S.venezuelae and jadomycin production were investigated. The growth of S.venezuelae was determined by measuring cell number and TF yield and the Jadomycin B was determined by measuring the optical density (AU¬526nm). Shocking the culture that was transferred after 18 h of growth in the growth medium produced the highest jadomycin, cell growth and activity compared to those that were transfered after 21 and 24 h. The culture shocked at a temperature of 40°C for 1 h produced the highest jadomycin. Higher temperature and/or longer exposure time resulted in poor cell growth and activity. The ethanol concentration of 4.5 % v/v produced the highest jadomycin. The culture shocked with ethanol once (0 h) produced higher jadomycin, cell growth and activity compared to the cultures shocked twice [(0, 3 h) and three times (0, 3 and 6 h)]. A nitrogen concentration of 75 mM with 4.5 % v/v in the production media increased cell growth and jadomycin production. The results showed that shocking the culture once with ethanol (3 % v/v) produced 81.5 % more jadomycin than shocking with heat at a temperature of 45°C for 1 h. However, increasing the ethanol concentration to 4.5 % v/v produced 10.8 % more jadomycin than 3 % v/v ethanol. By increasing the nitrogen concentration to 75 mM in the production medium and shocking with the 4.5 % v/v ethanol further increased the jadomycin production by 13.9 % above that without nitrogen addition. Therefore, the treatment with ethanol (4.5 % v/v) and nitrogen (75 mM) is recommended for jadomycin production.