Karakterisasi aktivitas antimikroba peptida bakteriosin rekombinan dan sintetik Bac1, Bac2, dan Bac3 serta efek sinerginya dengan ampisilin = Characterization of recombinant bacteriocin Bac1, Bac2, and Bac3 and their synthetic peptides for antimicrobial activity and synergistic effect with ampicilin