Nisin is an antimicrobial peptide that is commonly used as a food preservative and capable of inhibiting the pathogen Listeria monocytogenes. However, nisin is ineffective in controlling L. monocytogenes in Queso Fresco (QF). To address the challenge, in this work, we used synthetic biology strategies to create a series of nisin A derivatives by substituting residues 27, 30, 31 and 32 with positively charged amino acids (H, K and R). Our results showed that nisin derivatives exhibited reduced antilisterial activity in vitro compared to nisin A; however, they were all more stable under QF-like experimental conditions (pH 7 + 22% milk fat), notably H27/31K. Compared to nisin A, the derivatives H31K and V32K exhibited slight antilisterial improvement in QF and H27/31K was able to reduce the initial population of L. monocytogenes by up to 1.5 Log CFU/g. L. monocytogenes isolates exhibited similar susceptibility to nisin A or H27/31K after 7 or 14 days of nisin exposure in QF. Notably, when combined with endolysin PlyP100, the application of H27/31K resulted in non-enumerable levels of L. monocytogenes after 14 days of cold storage. Our results highlight the potential of bioengineered nisin derivatives for stabilized and enhanced control of L. monocytogenes in QF.

乳链菌肽是一种抗菌肽，通常用作食品防腐剂，并能够抑制病原体李斯特菌。然而，乳链菌肽在控制单核细胞增生李斯特氏菌方面无效。在Queso Fresco（QF）。为了解决这一挑战，在这项工作中，我们使用合成生物学策略通过用带正电荷的氨基酸（H，K和R）取代残基27、30、31和32来创建一系列乳链菌肽A衍生物。我们的结果表明，与乳链菌肽A相比，乳链菌肽衍生物在体外的抗李斯特菌活性降低。但是，它们在类似QF的实验条件下（pH 7 + 22％乳脂）都更稳定，尤其是H27 / 31K。与乳链菌肽A相比，衍生物H31K和V32K在QF中显示出轻微的抗利斯特氏菌改善，H27 / 31K能够将单核细胞增生李斯特菌的初始种群减少高达1.5 Log CFU / g。单核细胞增生李斯特菌在QF中暴露于乳链菌肽7或14天后，分离株对乳链菌肽A或H27 / 31K的敏感性相似。值得注意的是，当与内溶素PlyP100结合使用时，在冷藏14天后，H27 / 31K的应用导致单核细胞增生李斯特氏菌的数量不可计数。我们的结果突出了生物工程化的乳链菌肽衍生物对QF中单核细胞增生李斯特氏菌稳定和增强控制的潜力。