Researchers have focused on isolating and identifying the bacteriocin producing lactic acid bacteria from various food systems especially dairy products. Molecular techniques have been recently used for rabid identification of bacteriocins rather than time-consuming biochemical characters. Global climate disturbances can affect the diversity of beneficial microorganisms in dairy and their products, especially lactic acid bacteria, so it is worth to evaluate their bacteriocinogenicity in different climates. Thus, the aim of this study was to screen for predominant bacteriocin producing lactic acid bacteria (LAB) in traditional dairy products of Luxor governorate at Upper Egypt and determine their bacteriocin-encoding genes. Eighty-six strains of the LAB were isolated from raw milk and traditional dairy product of Luxor province, Egypt, in which 76.1% and 23.9% were identified as lactic acid bacilli and cocci, respectively. On the basis of their antibacterial potentials, 30 out of 68 LAB isolates were found to be antimicrobial producers. These isolates exhibited a potential antibacterial activity against Salmonella paratyphi B, Escherichia coli, Staphylococcus aureus, and Proteus mirabilis, except for Listeria monocytogenes. LAB isolates were analyzed using species-specific PCR; results emphasized that 22 of isolates were identified as Lactobacillus plantarum, while 8 were Leuconostoc mesenteroides. According to the sequencing of isolates, two strains named Lactobacillus plantarum Egypt 2018 (accession no. MH817034) and Leuconostoc mesenteroides Egypt 2018 (accession no. MH817035) were identified. Detection of bacteriocin-encoding genes was performed by polymerase chain reaction (PCR). The results emphasized that almost all tested Lb. plantarum strains (n = 10) possess both plnA and plnEF genes, whereas the gene encoding mesentericin Y105 was detected in one Lc. mesenteroides of the examined isolates. This study was effective for the rapid detection of bacteriocin producing strains within dairy products. Extracted bacteriocin could be a valuable source of natural food biopreservative.

中文翻译：

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埃及卢克索省传统乳制品中分离的乳酸菌细菌素编码基因的测定

研究人员致力于从各种食品系统，尤其是乳制品中分离和鉴定产生细菌素的乳酸菌。分子技术最近已用于狂热鉴定细菌素，而不是费时的生化特征。全球气候干扰会影响奶制品及其产品中有益微生物的多样性，尤其是乳酸菌，因此有必要评估其在不同气候下的致细菌性。因此，本研究的目的是在上埃及卢克索省传统乳制品中筛选出主要产生细菌素的乳酸菌（LAB），并确定其细菌素编码基因。从埃及卢克索省的原奶和传统乳制品中分离出86株乳酸菌菌株，其中76株。乳酸杆菌和球菌分别占1％和23.9％。根据其抗菌潜能，发现68株LAB菌株中有30株是抗菌素生产者。除了李斯特菌外，这些分离株还表现出对副伤寒沙门氏菌B，大肠杆菌，金黄色葡萄球菌和奇异变形杆菌的潜在抗菌活性。使用物种特异性PCR分析LAB分离物；结果强调，分离株中有22株被鉴定为植物乳杆菌，而肠膜十二指肠球菌为8株。根据分离物的测序，鉴定了两个名为植物乳杆菌埃及2018（登录号MH817034）和中肠隐球菌Leuconostoc mesenteroides 2018（登录号MH817035）的菌株。细菌素编码基因的检测通过聚合酶链反应（PCR）进行。结果强调，几乎所有测试的Lb。植物乳杆菌菌株（n = 10）同时具有plnA和plnEF基因，而在一个Lc中检测到编码肠系膜素Y105的基因。检查过的分离物的肠膜肠膜。这项研究有效地快速检测了乳制品中产生细菌素的菌株。提取的细菌素可能是天然食品生物防腐剂的宝贵来源。