RESUMO
The soil samples were collected from primeval forest, alpine meadow, marshy, grainfield and vegetable farmland ect. 9 different kinds of Vegetative type and from 2970 - 4590 altitude of southeastern of Tibet. The amount,composition, antimicrobial activity of mesophilic and psychrophilic actinomycetes and some mesophilic actinomycetes of physiological and biochemical characteristics were studied by normal methods. These actinomycetes were identified at genus level by their morphological properties. Results indicated that: (1) 9 genus of actinomycetes were isolated from soil and Actinosynnema was never reported in China. Grain field contains the largest quantity of actinomycetes. (2) Primeval forest contains the largest quantity of antimicrobal actinomycetes, so more and more antimicrobal actinomycetes information can be obtained from them. (3) The strains tested had stronger antimicrobial activity against Gram-positive bacteria than Gram-negative bacteria, had stronger antimicrobial activity against fungi than bacteria. (4) Many strains of streptomyces have some enzyme activities such as gelatin utilization, Milk-clotting enzyme etc.
