Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot 010018, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China.
Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot 010018, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China.
Int J Food Microbiol. 2024 Oct 2;423:110833. doi: 10.1016/j.ijfoodmicro.2024.110833. Epub 2024 Jul 22.
Phage infection remains a major cause of fermentation failures in the dairy industry. The development of phage-resistant mutants of important fermentation strains is an effective measure used to address phage-related issues. This study employed the secondary culture method to screen for spontaneous phage-resistant mutants from the phage sensitive strain Limosilactobacillus fermentum IMAU32646 (L. fermentum IMAU32646). The phenotypic characteristics, technological attributes, probiotic characterization, adsorption characteristics and mutant genes were investigated. The results showed that the mutant strain displayed a high degree of phage-resistance and stability. The mutant strain produced more lactic acid during fermentation than the sensitive strain, while maintaining identical cell structure and morphologies. The mutant strain exhibited superior tolerance to acid and bile salts compared to the sensitive strain. Furthermore, the adsorption rate of phage LFP01 on the mutant strain was significantly lower than that of the sensitive strain. Following genome re-sequencing analysis showed that adsorption interference and blocked DNA injection were responsible for its phage-resistance. These results may provide a new strategy for avoiding phage contamination and industrial application of phage-resistant strains with good characteristics.
噬菌体感染仍然是乳品工业发酵失败的主要原因。开发重要发酵菌株的抗噬菌体突变体是解决噬菌体相关问题的有效措施。本研究采用二级培养法从噬菌体敏感菌株植物乳杆菌 IMAU32646（L. fermentum IMAU32646）中筛选自发产生的抗噬菌体突变体。对其表型特征、工艺特性、益生菌特性、吸附特性和突变基因进行了研究。结果表明，突变株表现出高度的噬菌体抗性和稳定性。突变株在发酵过程中产生的乳酸量高于敏感株，同时保持相同的细胞结构和形态。与敏感株相比，突变株对酸和胆盐的耐受性更好。此外，噬菌体 LFP01 对突变株的吸附率明显低于敏感株。全基因组重测序分析表明，吸附干扰和阻断 DNA 注射是其抗噬菌体的原因。这些结果可能为避免噬菌体污染和具有良好特性的抗噬菌体菌株的工业应用提供新的策略。
