the present invention provides mutants mass - producing εpl which are obtained by mutation treatment of a strain producing εpl . for using the mutants , the mutants are cultured in a cultivated medium , εpl is mass - produced and stored in the culture solution , and the stored εpl is collected from the solution . for producing εpl , a strain which produces εpl is mutation - treated , the obtained mutant is cultivated in a culture medium to which l - lysine or l - lysine and one or more sugars are added , εpl is mass - produced and stored in the culture solution , and the stored εpl is collected from the solution . the mutants producing εpl in large quantities are preferably the mutants which have tolerance to an analogue of l - lysine of streptomyces albulus subsp . lysinopolymerus no . 346 - d strain and chloramphenicol - treated mutant of the same bacteria .