Antimicrobial Activity and Genomic Analysis of <i>Lactococcus lactis</i> Strains NRRL B-50571 and NRRL B-50572 Isolated from Artisanal Mexican Cheese for the Assessment of their Biotechnological Potential as Starter Cultures

The objective of this study was to report the genome sequence of <i>Lactococcus lactis</i> NRRL B-50571 and NRRL B-50572, <i>in silico</i> analysis for the identification of genes related with their biotechnological potential and to evaluate the antimicrobial properties <i>in vitro</i>. Results demonstrated the safety of these strains, since they did not exhibit antibiotic resistance genes or links to pathogenic families. Genes related to probiotic properties, amino acid biosynthesis and catabolism, vitamin production and carbohydrate metabolism, bacteriocins and secondary metabolites were found. Also, these strains produced bacteriocin-like substances which exhibited antimicrobial activity against food indicator microorganisms (<i>Staphylococcus aureus</i>, <i>Listeria innocua</i>, <i>Salmonella enterica</i> subsp. <i>enterica</i> serovar Typhimurium, <i>Salmonella enterica</i> subsp. <i>enterica</i> serovar Choleraesuis and <i>Escherichia coli)</i>. These findings provided valuable insights into the genomic and functional capabilities of <i>L. lactis</i> NRRL B-50571 and NRRL B-50572, highlighting their biotechnological significance for their use as starter cultures in the manufacture of safe dairy foods with potential health benefits.本研究旨在解析乳酸乳球菌（Lactococcus lactis）NRRL B-50571与NRRL B-50572的基因组序列，开展生物信息学（in silico）分析以鉴定与其生物技术应用潜力相关的基因，并通过体外（in vitro）实验评估其抗菌性能。实验结果证实了这两株菌株的安全性：未检测到抗生素抗性基因，且未与致病菌群存在关联。研究鉴定出了与益生菌特性、氨基酸生物合成与分解代谢、维生素合成、碳水化合物代谢、细菌素（bacteriocins）及次级代谢产物相关的基因。此外，这两株菌株可产生类细菌素物质，对食品指示微生物——金黄色葡萄球菌（Staphylococcus aureus）、无害李斯特菌（Listeria innocua）、鼠伤寒沙门氏菌（Salmonella enterica subsp. enterica serovar Typhimurium）、猪霍乱沙门氏菌（Salmonella enterica subsp. enterica serovar Choleraesuis）及大肠杆菌（Escherichia coli）——均具有抗菌活性。本研究结果为乳酸乳球菌NRRL B-50571与NRRL B-50572的基因组及功能特性提供了重要见解，凸显了其作为发酵剂菌种用于生产安全乳制品并潜在带来健康益处的生物技术应用价值。