A potential bacteriocin gene was isolated from 18575 ORFs by bioinformatics methods. It was named pin1, and cloned into pET32a. Then, it was expressed as a thioredoxin-Pln1 fusion protein in Escherichia coli BL21 (DE3). The fusion protein was purified by Ni-NTA, and thioredoxin was removed by enterokinase. Finally, Pln1 was purified using a cation affinity column. The yields of fused and cleaved Pln1 peptides were 100-110 mg/l and 9-11 mg/l, respectively. Pln1 was stable in an acidic environment and at temperatures below 60 degrees C, but was easily degraded under alkaline conditions and by protease treatment. The cleaved and purified Pln1 showed strong antimicrobial activity against gram-positive bacteria such as Micrococcus luteus CMCC 63202, Staphylococcus epidermidis, Lactococcus lactis NZ3900, Lactobacillus paracasei CICC 20241, and Listeria innocua CICC 10417. In particular, Pln1 had a better activity against methicillin-resistant S. epidermidis (MRSE) than nisin, thereby offering an attractive approach to counter bacterial antibiotic resistance. (C) 2015 Elsevier Inc. All rights reserved.