Improvement of erythromycin production by Saccharopolyspora erythraea in molasses based medium through cultivation medium optimization.

In the present work, erythromycin production was carried out in submerged culture using Saccharopolyspora erythraea. Different experiments were conducted to optimize the cultivation medium through the change of carbon and nitrogen sources to cheaper one in order to reduce the cost of medium and to utilize sugar cane molasses as one of major sugar industry by-products in Egypt. It was found that the addition of sugar cane molasses a sole carbon source at a concentration of 60 g/l accompanied by corn steep liquor (as organic N-source) in combination with ammonium sulphate (as inorganic N-source) gave the maximal erythromycin production. The antibiotic production in this medium reached about 600 mg/l which is about 33% higher than the value obtained in glucose based medium. On the other hand, the addition of n-propanol in concentration of 1% (v/v) increased the antibiotic production reaching about 720 mg/l after 144 h. Concluding, the new medium formulation based on cheap carbon source, sugar cane molasses, was a good alternative solution for the production of erythromycin economically.

Optimization of the cultivation medium for natamycin production by Streptomyces natalensis.

The effects of certain nutrients on natamycin production by Streptomyces natalensis in submerged batch culture were studied. The production of this antibiotic required glucose in the cultivation medium with a concentration of 20 g/l. On the other hand, the highest antibiotic production was obtained in a cultivation medium containing 0.05 g/l of potassium dihydrogen phosphate. Further increase in phosphate concentration resulted in a significant increase in biomass concomitant with lower antibiotic production. Among different N-sources tested, only ammonium sulphate, sodium nitrate and beef extract were the suitable nitrogen sources in supporting the antibiotic production. Furthermore, a mixture of beef extract and yeast extract (8 g/l and 2 g/l, respectively) exhibited a synergistic effect in enhancing the natamycin production reaching about 1.5 g/l.

Studies of rifamycin production by Amycolatopsis mediterranei cells immobilized on glass wool.

Cells of Amycolatopsis mediterranei CBS 42575 were immobilized on glass wool for the production of rifamycins B and SV. Glass wool (CORNING type) of 8 microns in diameter has a better entrapment capacity for microbial cells of microorganism than the other types of glass wool used. The most suitable amount of glass wool was 0.8 g/50 ml. The best initial cell concentration used as inoculum was 40 mg cells/50 ml. Repeated batch production of rifamycins by immobilized cells on glass wool was carried out for 6 repeated batches. The results showed that reduction of batch time from 96 h to 48 h does not decrease rifamycin production by immobilized cells.

Production and properties of fibrinolytic enzyme fromStreptomyces sp. NRC 411.

Of 16Streptomyces spp. investigated for the production of extracellular fibrinolytic enzyme, one species was chosen as the most promising producer. Using shaken cultures grown for 7 days, optimal conditions for enzyme production were pH 6.0, 5% (w/v) starch as carbon source, (NH4)2SO4 and soybean flour as nitrogen sources and KH2PO4 at 1.2 g/l. Maximal activity of the crude enzyme was at pH 6.0 and 45°C. Holding the enzyme at 37°C for 2 h decreased the activity by only 10%.

Cellulose-decomposing fungi.

The present article gives a survey of the cellulose-decomposing fungi. It is concerned with the micro-organisms having the capability of degradating cellulose sources. It includes the factors influencing cellulose-decomposing fungi, cellulose-decomposing enzymes, mechanisms of degradation, and factors influencing the cellulolytic enzymes (cellulases).