LAUSR

The challenge of finding out new methodologies and strategies for improving production of the multifunction highly potent medication “rapamycin by Streptomyces hygroscopicus ATCC 29253 was adopted in the current study. Nano-sizing of soy meal, as a key nutrient in rapamycin production, was employed using three different sizes (89, 59.75 and 49 nm) and little enhancement was observed in case of size 89 nm. On the other hand, using concentrated production media showed for the first time an impressive effect on rapamycin production where it was attainable to get a superior exclusive increase (129.7%) in the yield using 1.5-fold concentrated medium. Modulating the salinity level in production medium promoted the production; 56.4% increase in the yield has been achieved with 1% NaCl. Repeated inoculation of the production medium with the producer strain was proven to be non-effective. The suspected stimulatory role of co-culturing the yeast Candida albicans with the producer strain, enriching the production medium with camel milk and managing the feedback inhibitory mechanisms were also realized. Production of rapamycin under fluctuated incubation temperature was one of novel tested stimulators and it has achieved a tremendous increase in yield (about 132%) associated with marked increase in the growth of producing strain.