Utilization of date products in production of oxytetracycline by Streptomyces rimosus.

The carbon and nitrogen sources of a synthetic fermentation medium were substituted by equivalent amounts of date-coat sugar extract and date-seed hydrolysate. The addition of 1.0 g dm-3 urea and date-seed lipid into the medium increased the efficacy for antibiotic formation. When the MgSO4, MnSO4, FeSO4 and ZnSO4 components of the medium were replaced by 0.5 g dm-3 date-seed ash, antibiotic output was also increased.

Production of oxytetracycline by Streptomyces rimosus 12,907 as an animal feed supplement.

Production of oxytetracycline by Streptomyces rimosus 12907 as an animal feed supplement was achieved with a fermentation medium, containing the following ingredients (g/litre): black strap molasses, 30; fodder yeast, 20; rice bran, 10; KH2PO4, 0.2; and tap water to 1,000 ml. The dry mash, containing oxytetracycline, was 50 g/litre of fermentation medium. The amount of oxytetracycline, present in the dry mash, was about 4.0%. The dry mash, containing oxytetracycline, contained the following amino acids: L-arginine, L-histidine, L-lysine, L-isoleucine, L-leucine, L-phenylalanine, Dl-methionine, and L-tryptophan.

Spiramycin, a macrolide antibiotic.

Spiramycin is produced by Streptomyces ambofaciens. It is a mixture of compounds, similar in their elementary composition as well as in their physical, chemical, and bacterial properties. Its anti-bacterial spectrum includes mainly Gram-positive organisms and Neisseria. The fermentation medium of Streptomyces ambofaciens consists of corn steep liquor, glucose, CaCO3, NaCl, and MgSO4. Mode of action of spiramycin on microorganisms was represented in the review article. Spiramycin is used in animal nutrition, especially in poultry.

Influence of micronutrients on citric acid production by Candida lipolytica (Y 1095).

FeSO4 . 7 H2O, PbSO4, CuSO4 . 5 H2O, MnSO4 . 4 H2O, ZnSO4 . 7 H2O, CoCl2 . 6 H2O, and (NH4)6Mo7O24 . 4 H2O were added to the fermentation medium to investigate their potentialities on citric acid production by Candida lipolytica (Y 1095). FeSO4 . 7 H2O and MnSO4 . 4 H2O were more suitable than the other micronutrients for citric acid production. Addition of certain amino acids to the fermentation medium completely inhibited biosynthesis of citric acid by Candida lipolytica (Y 1095). When the fermentation medium was supplied with certain vitamins, yield of citric acid was increased in the presence of thiamine, nicotinic acid, and nicotinamide. The optimum concentration of thiamine which favoured yield of citric acid was 6 mg/l.

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).

Fermentative production of fodder yeasts.

Fermentative production of fodder yeasts are achieved by different microorganisms of yeast. Influence of some biochemical factors on the formation of fodder yeast are examined. The raw ingredients and by-products which are used in the fermentative formation of fodder yeast are also reviewed.

Antibiotic NRC-501, a new antibiotic produced by Streptomyces species.

A new antibiotic, NRC-501, was isolated and purified from the fermentation broth of Streptomyces species NRC-501. Physical, chemical, and biological characteristics of the antibiotic NRC-501 were revealed.

Production of gentamicins by Micromonospora purpurea.

The natural medium contained the following ingredients (g/l): glucose 8.0, or black strap molasses (treated with 0.2--0.3 g/l EDTA) 12.0, fodder yeast (50.0% total nitrogen) 2.0, or folder yeast (40.0% total nitrogen) 6.0, or yeast extract 8.0, or tryptone 8.0, and CaCO3 1.0. Treated black strap molasses with EDTA and fodder yeast proved to be effective in the fermentative production of gentamicins. The most suitable chelating agent was EDTA in the form of disodium for the treatment of Komombo molasses in a concentration of 0.2--0.3 g/l, while potassium ferrocyanide and methylene blue had depressing effects on the production of gentamicins. The most effective carbon source, present in Egyptian black strap molasses, was glucose. Addition of glucose to the medium was preferable at the beginning of the fermentation process. Trace elements present in molasses were very essential for the microbial growth and biosynthesis of gentamicins as proved when molasses ash was added to the natural medium. Organic nitrogen sources were more suitable than inorganic nitrogen sources for the production of gentamicins by Micromonospora purpurea. The microorganism utilized the synthetic medium, but the antibiotic yields were less than those produced in the natural medium. The synthetic medium exhibited stimulatory effects of certain amino acids, organic acids, vitamins, and purine and pyrimidine bases on the fermentative production of gentamicins. Therefore, the ingredients increasing yields of gentamicins were mainly phenylalanine, iso-leucine, lysine, methionine, leucine, arginine, glycine, beta-alanine, cystine, tryptophan, malic acid, maleic acid, cobalamin, folic acid, riboflavin, vitamin B1, vitamin B6, biotin, nicotinamide, uracil, adenine, guanine, and adenosine. Trace elements (Co, Mo, Fe, Cu, Zn, and Mn) exhibited their important role on the biosynthesis and production of gentamicins by Micromonospora purpurea.