PURPOSE: To increase the yield of the subject antibiotic, by supplying acid hydrolyzed casein and propionate to the culture product prepared by a specific Actinomadula sp.

CONSTITUTION: Acid hydrolyzed casein is intermittently or continuously supplied at a rate of about 2.50-about 7.50 g/L, day to the culture product of Actinomadula fibrosa sp. nov. NRRL 18348 (or its mutant capable of producing antibiotic A82810) during a period from a time after about 15 to about 35 hours from the beginning of the production to a time to produce a recoverable amount of antibiotic A82810. Further, propionate is intermittently or continuously supplied at a rate of about 0.50-about 1.50 g/L day to the culture product during a period from a time after about 25 to about 70 hours from the beginning of the production to a time to produce a recoverable amount of antibiotic A 82810. The antibiotic A82810 is shown by the formula as a polyether-based anti bacterial and anticoccidial medicine.