Enterococcus faecium CCM4231, isolated from the rumen content of a calf, produced an antimicrobial agent active against Gram‐positive and Gram‐negative indicator organisms. After 100‐fold concentration by ultrafiltration, the diameters of zones of inhibition ranged from 2 to 10 mm. The agent was sensitive to pronase and trypsin and resistant to heating at 60°C for 30 min.

The new bacteriocin, termed enterocin M, produced by Enterococcus faecium AL 41 showed a wide spectrum of inhibitory activity against the indicator organisms from diVerent sources. It was puriWed by (NH 4 ) 2 SO 4 precipitation, cation-exchange chromatography and reverse phase chromatography (FPLC). The puriWed peptide was sequenced by N-terminal amino acid Edman degradation and a mass spectrometry analysis was performed. By combining the data obtained from amino acid sequence (39 Nterminal amino acid residues was determined) and the molecular weight (determined to be 4 628 Da) it was concluded that the puriWed enterocin M is a new bacteriocin, which is very similar to enterocin P. However, its molecular weight is diVerent from enterocin P (4 701.25). Of the Wrst 39 N-terminal residues of enterocin M, valine was found in position 20 and a lysine in position 35, while enterocin P has tryptophane residues in these positions.

Aims:The partial characterization of bacteriocins produced by an environmental strain Enterococcus faecium EK13, isolated from cattle dung water. Methods and Results: A bacteriocin was partially purified by ammonium sulphate precipitation, followed by a SP-Sepharose column, reverse-phase chromatography and N-terminal region sequenced. The anti-microbial substance produced was found to be a heat-stable polypeptide with molecular mass 4AE83 kDa, which was determined by N-terminal amino acid sequencing to be enterocin A. A second substance was specified by PCR as enterocin P. Bacteriocins were stable at 4 and )20°C for long storage periods. The optimum of bacteriocin production was observed in the range of pH 5AE0-6AE5 at 30 and 37°C. The most active substances are produced by strain EK13 in logarithmic growth phase and bacteriocins are produced after 1 h of fermentation. The highest activity detected in fermentation experiments was 51 200 AU ml )1 and the most sensitive indicator strain was found to be Listeria innocua LMG 13568. Differences in bacteriocin activity against two indicators could be explained by more than one type of enterocin production by strain EK13, or with different mode of action or in different sensitivity of strains. Conclusion: Enterococcus faecium strain EK13 isolated from cattle dung water produces two bacteriocins, enterocin A and P, with an inhibitory effect against the strain of the genera Enterococcus, Leuconostoc, Lactobacillus, Streptococcus, Staphylococcus, Bacillus and Listeria (in different origin). Significance and Impact of the Study: Enterococcus faecium EK13 environmental strain is a new producer of enterocin A and P. The E. faecium EK13, isolated from cattle dung water, is presented with the further aim to utilize it for waste treatment by biotechnological processes.

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