FIELD: biotechnology, microbiology. SUBSTANCE: strain Streptomyces avermitilis NITSB 132 is obtained from the parent strain Streptomyces avermitilis 103 by selection on agarized medium containing antibiotic streptomycin followed by isolation of mutants showing resistance to streptomycin at concentration 0.5 mcg/ml, selection of mutants showing the highest production of avermectins (3500 mcg/ml, not less), avermectin B1(a + b) (1500 mcg/ml, not less) and control of the strain for its ability to retain properties under culturing conditions. Strain can be used for industrial production of avermectins, among them avermectin B1(a + b). EFFECT: strain indicated above, increased yield of avermectins. 2 ex
