A newly discovered bacteriocin from Weissella hellenica D1501 associated with Chinese Dong fermented meat (Nanx Wudl)

A new strain D1501, isolated from Chinese traditional Dong fermented meat (Nanx Wudl) and identified as Weissella hellenica, produced a bacteriocin (designated as weissellicin D) in de Man–Rogosa–Sharpe (MRS) broth at the early stationary phase. The bacteriocin was purified to homogeneity by ammonium sulfate precipitation, gel permeation and Mono-Q anion-exchange chromatography. Weissellicin D had a molecular weight of 62.42 kDa by Tricine–SDS-PAGE and mass spectrometry, which was the largest among all known bacteriocins from Weissella. Weissellicin D exhibited a broad range of antimicrobial activity against food-borne spoilage and pathogenic bacteria such as Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, as well as some yeasts and molds. Weissellicin D showed strong pH and thermal stabilities. It was sensitive to protease, but resistant to catalase, lipase, α-amylase, lysozyme, and glucoamylase. The Edman degradation results implied that amino acid sequences of weissellicin D were belonged to N-terminal blocking group. Peptide mass fingerprinting (PMF) analyses after trypsin digestion indicated weissellicin D had no homology with any known bacteriocins or antimicrobial proteins. This was the first description of W. hellenica strain associated with Chinese Dong fermented meat as well as the high molecular weight of bacteriocin produced by this strain.