乳酸菌的热胁迫研究进展

Research Progress on Heat Stress of Lactic Acid Bacteria

乳酸菌和其他自由生活的微生物一样,在发酵及食品加工、贮藏过程中经常暴露于各种环境胁迫条件下,包括饥饿胁迫、渗透压胁迫以及热胁迫等,增加胁迫抗性是提高生物量及代谢产物积累的有效策略。热胁迫可能是自然界及工业应用中微生物所面临的最常见压力。目前研究表明来自不同生境的乳酸菌通过基因表达的快速变化对温度的突然升高做出反应,从而导致热休克蛋白的蛋白质水平升高。热休克蛋白在进化过程中具有高度保守性,在正常条件下,其有助于受体调节,细胞骨架稳定及蛋白质的折叠、组装、运输、降解。在热胁迫条件下,其功能变得尤为重要。综述了乳酸菌的热胁迫耐受机制及不同乳酸菌的热胁迫反应,为研究乳酸菌热胁迫应答机制提供一定的理论借鉴,有利于乳酸菌的工业化应用。

Lactic acid bacteria(LAB),like other free-living microorganisms,are usually exposed to various environmental stress conditions in the course of microbial fermentation,food processing and storage,which include starvation stress,osmotic stress,and heat stress.Enhancement of stress resistance is considered an effective strategy for better cell growth and increased the yield of metabolites.Heat stress is probably the most common stress,which bacteria and other organisms are confronted in the natural world and industrial applications.Some studies had demonstrated that LAB from different habitats responded to a sudden increase in temperature by rapid changes in gene expression resulting in elevated levels of heat-shock proteins(HSPs).Under normal conditions,HSPs assist in receptor regulation,cytoskeleton stabilization,and protein folding,assembly,transport,degradation,and under heat stress these functions become especially important.In this paper,the tolerance mechanism of heat stress in LAB and heat stress reaction of different LAB were discussed in order to provide a theoretical reference for the study of the heat stress response mechanism in LAB and to facilitate the industrial application of LAB.