乳酸菌细菌素抑菌特性及在食品中的应用研究进展

乳酸菌细菌素是细菌在核糖体上合成的具有抗菌活性的多肽类物质,这些细菌素能杀灭或抑制引起食品腐败的细菌的繁殖,可作为天然的食品防腐剂在食品中应用。该文综述了乳酸菌细菌素的分类、国内外研究现状、抑菌特性及应用等方面的最新研究进展,并对乳酸菌细菌素未来研究趋势进行简要分析,对乳酸菌细菌素在食品中的应用有一定参考价值。     

乳酸菌细菌素的作用机制及在肉制品中的应用

乳酸菌细菌素是乳酸菌在代谢过程产生的一类具有抗菌活性的多肽或蛋白质,在各类食品中均有广泛应用。作为一种生物防腐剂,肉制品中添加乳酸菌细菌素可以抑制腐败菌和致病菌生长,从而提高产品的安全性和延长保质期。综述乳酸菌细菌素的分类、生物合成、作用机制及在肉制品中的应用,为建立乳酸菌细菌素防腐体系提供理论依据。     

乳酸菌细菌素抗菌潜力挖掘研究进展

乳酸菌产生的主要抗菌防腐物质是有机酸,但在乳酸菌代谢产物中发现了细菌素等其它抗菌物质,其中有的细菌素甚至具有强烈的抗真菌能力。世界范围内启动的乳酸菌基因组计划创造了巨大的生物信息流。乳酸菌基因组蕴含的生物信息将对研究乳酸菌细菌素的合成代谢途径,功能基因挖掘以及新型抗菌剂的开发搭建信息平台。结合乳酸菌细菌素的最新研究进展,讨论利用乳酸菌基因组探索乳酸菌的抗菌潜力及其作为生物防腐剂在食品保藏中的应用前景。     

群体感应系统在乳酸菌产细菌素中的作用

许多乳酸菌能够产生抗菌活性肽——细菌素,细菌素具有不同的结构、作用方式、抑菌谱和效价,通常认为乳酸菌和其所产的细菌素都是安全的,乳酸菌所产细菌素作为天然食品防腐剂已显示了巨大的潜能。基于群体感应的细胞间交流已成为细菌素合成的关键调控机制,群体感应作为细胞密度函数,可使细菌素产生保持同步性。群体感应需通过信号分子介导感知菌体密度,信号分子随着菌体密度增加而增加,并激活信号转导级联使菌体产生细菌素。本文通过对乳酸菌群体感应信号分子种类、信号转导机制及群体感应系统对两类细菌素合成的调控进行综述,以初步了解群体感应系统在乳酸菌产细菌素过程中的作用机制。     

乳酸菌细菌素抗菌作用机制研究进展

乳酸菌细菌素是由乳酸菌在代谢过程中通过核糖体合成机制产生的一类具有抗菌活性的多肽。已有的研究表明乳酸菌细菌素具有作为食品防腐剂的潜力,目前由乳酸链球菌产生的Nisin已被允许作为食品防腐剂。然而,很多具有良好抗菌活性的细菌素,因抗菌作用机制不明确,限制了其在食品等领域的应用。显微技术、细胞模型制备、荧光探针技术、圆二色谱技术等被用于乳酸菌细菌素抗菌作用机制的研究。乳酸菌细菌素抗菌作用机制包括细胞膜损伤机制和细菌素的胞内作用形式。其中以细胞膜损伤机制为主,这一机制又包括无特异性靶点的"膜穿孔"机制及有特异性靶点(如Lipid Ⅱ和某些膜蛋白)的作用机制。乳酸菌细菌素的胞内作用形式是通过干扰细胞内核酸和蛋白质等物质的正常代谢来发挥抗菌作用。乳酸菌细菌素的抗菌作用机制并不是单一的,一种细菌素可以通过多种不同的作用机制发挥作用,而同一种细菌素对于不同的靶细胞也会有不同的作用机制。探讨细菌素的抗菌作用机制,可为其在多领域的高效应用提供良好的科学依据。     

乳酸菌细菌素的分类、生物合成及其应用

细菌素是细菌在核糖体上合成的具有抗菌活性的多肽.许多乳酸菌都能生产细菌素,这些细菌素在同一生境中能杀灭或抑制引起食品腐败的细菌和病原菌的繁殖,可作为天然的食品防腐剂在食品中应用.综述主要描述了乳酸菌细菌素的分类、生物合成及其应用.     

安全的天然食品防腐剂细菌素

细菌素是细菌产生的可以杀死或抑制别的细菌生长的抗菌蛋白。许多乳酸菌(LAB)产生各种各样的细菌素，其中的尼生素是唯一的在食品中作为防腐剂广泛使用的细菌素。文章综述了以尼生素为重点对细菌素与抗生素的区别、活性细菌素分子的形成以及其在食品中的应用，并比较了这两种类型的分子的合成、作用模式、抵抗力和安全性。     

乳酸菌合成细菌素及对肠道菌群的影响

细菌素是一类由细菌核糖体合成的抗菌肽,目前是食品、医药等多个学科领域的研究热点。乳酸菌在食品中的应用由来已久,通常被认为是一种安全的微生物,并且有助于促进肠道健康,因此其合成的细菌素具有很大的实际应用潜力。近年来人们对肠道菌群的关注度不断提高,同时随着乳酸菌的广泛应用及对其益生机制的不断探究,关于乳酸菌合成的细菌素对肠道菌群影响的研究显得意义重大。该文基于相关研究进展,阐述了乳酸菌合成的细菌素的分类、特点、应用及其对肠道菌群的影响,以期为功能性乳酸菌及乳酸菌细菌素的开发利用提供基础理论依据。     

乳酸菌细菌素研究进展及其在水产养殖和加工中的应用

乳酸菌细菌素是一种由乳酸菌在核糖体内合成、具有抑菌活性的多肽或蛋白质。由于乳酸菌通常被认为是安全的微生物,因此由它产生的细菌素受到了广泛地关注。目前由于大部分乳酸菌细菌素抑菌机理研究还不够深入,在一定程度上限制了它的发展和应用。本文对现有乳酸菌细菌素研究成果进行总结,并对细菌素进行了系统分类,阐述了各类乳酸菌细菌素对革兰氏阳性菌的作用机理,最后介绍了乳酸菌细菌素在水产养殖、水产品加工贮藏过程中的应用,旨在为乳酸菌细菌素的应用提供新的探索和基础理论依据。     

一株乳酸菌细菌素的检测及其产生的最佳条件的研究

以一株分离自牙鲆肠道的乳酸菌L15为材料,用打孔法检测其发酵上清液对枯草杆菌、大肠杆菌、金黄色葡萄球菌的抑制作用。排除有机酸和过氧化氢的干扰,证明上清液中含有抗菌的活性成分;用蛋白酶处理后,抑菌活性明显降低,表明起抑菌作用的是蛋白类物质的细菌素。研究表明,培养温度30℃、时间48h、pH值为7时是乳酸菌细菌素的最佳产生条件。对乳酸菌发酵上清液中的细菌素进行分离纯化,SDS-PAGE电泳表明乳酸菌的细菌素是一种具有抗菌活性的多肽,蛋白或蛋白复合物。     

乳酸菌细菌素的抑菌活性测定及效价表示方法

细菌素是某些细菌所产生的一类具有抑菌活性的代谢产物,它由于高效、无毒、不产生抗药性等优良特点,近年来作为生物抑菌剂得到广泛应用。目前应用于实际生产中的细菌素只有有限几种,而且细菌素受自身性质的局限,并非在任何环境下都能发挥应有效应,只有不断挖掘新鲜高效的细菌素产品,才能推动生物防腐技术的发展。目前判定细菌素抑菌效果的主要检测方式为琼脂扩散法和浊度法,而随着技术的进步,一些新型高效的方法如辐射法、ELISA试剂盒以及生物工程技术有望成为有效的替代方法。本文着重综述了在细菌素抑菌活性测定时样品制备中应注意的一些问题,同时较全面地比较了细菌素抑菌活性的测定方法以及细菌素效价的表示方式,以助于提高研究结果表示的规范性,为相关研究以及细菌素更好地应用到生物技术领域提供帮助和指导。     

Detection and preliminary characterization of a bacteriocin (plantaricin 35d) produced by a Lactobacillus plantarum strain

Lactic acid bacteria (134) from Italian sausages were tested for the production of antimicrobial substances (bacteriocins). Six percent of these showed antibacterial activity against one or several closely related microorganisms used as indicators. Lactobacillus plantarum 35d in particular produced a bacteriocin of high activity (320 AU ml(-1)) and a wide range of antimicrobial activity including S. aureus, L. monocytogenes, and A. hydrophila. The bacteriocin withstood heating at 80 degrees C for 120 min and storage at 4 degrees C for 6 months. The mode of action was identified as bactericidal. The apparent molecular weight of the bacteriocin extracted with n-butanol was estimated to be 4.5 kDa.     

提高乳酸菌细菌素合成量方法的研究进展

细菌素是某些细菌通过核糖体合成机制产生的蛋白质或多肽,能够抑制与其亲源关系相同或相近的微生物,某些细菌素在食品加工和发酵过程中能抑制致病菌和腐败菌。乳酸菌被认为是一般公认安全,其细菌素具有安全性高、稳定性好、抑菌谱广等优点,作为一种新型食品防腐剂备受关注,但商品化的乳酸菌细菌素十分有限,仅限于Nisin和Pediocin PA-1等少数几种,合成量低是细菌素在食品中应用受限的主要原因之一。从不同原料中筛选高产菌株、发酵培养基和发酵条件优化、诱变育种、原生质体融合、基因工程方法、群体感应系统调控六个方面,论述了增加乳酸菌细菌素合成量的方法,以期为实现乳酸菌细菌素的工业化生产提供一定的借鉴。     

A comparative study on the use of flow cytometry and colony forming units for assessment of the antibacterial effect of bacteriocins

Flow cytometry was investigated as a rapid method to determine the antibacterial effect of the bacteriocins nisin, pediocin PA-1, and sakacin A on the indicator organisms Lactobacillus reuteri DSM 12246, Lactobacillus sakei NCFB 2714 and Lactobacillus sakei DSM 20017, respectively. Fluorescence intensities of the cells were measured by flow cytometry upon exposure to bacteriocins after staining with carboxyfluorescein diacetate (cFDA) and were compared to the number of colony forming units (CFU). The fluorescence index (FI) of the bacterial populations decreased when exposed to the bacteriocins. For the different bacteriocins the pattern of decreases in FI and colony forming units differed at equal bacteriostatic concentrations. FI was the most sensitive measure of bacteriocin activity, i.e. the decrease in FI was observed at lower bacteriocin concentrations than decrease in CFU. It was demonstrated that the decrease in FI was caused by rapid leakage of carboxyfluorescein from cells exposed to pediocin. Cells showing severe leakage after pediocin treatment could be detected as CFU when transferred to a rich medium. Such a repair was less pronounced for cells exposed to sakacin and very limited for cells exposed to nisin. The influence of temperature and NaCl in combination with pediocin on FI and CFU of Lactobacillus sakei NCFB 2714 was examined at conditions relevant to foods. At all temperatures (5, 10, 20 and 37 degrees C) and NaCl concentrations (0, 2 and 4% w/v) investigated the flow cytometric measurements were significantly more sensitive compared to CFU. Both methods showed that the inhibitory effect of pediocin increased with increasing temperatures and decreased with increasing NaCl concentrations.     

Bacteriocins: safe, natural antimicrobials for food preservation.

Bacteriocins are antibacterial proteins produced by bacteria that kill or inhibit the growth of other bacteria. Many lactic acid bacteria (LAB) produce a high diversity of different bacteriocins. Though these bacteriocins are produced by LAB found in numerous fermented and non-fermented foods, nisin is currently the only bacteriocin widely used as a food preservative. Many bacteriocins have been characterized biochemically and genetically, and though there is a basic understanding of their structure-function, biosynthesis, and mode of action, many aspects of these compounds are still unknown. This article gives an overview of bacteriocin applications, and differentiates bacteriocins from antibiotics. A comparison of the synthesis. mode of action, resistance and safety of the two types of molecules is covered. Toxicity data exist for only a few bacteriocins, but research and their long-time intentional use strongly suggest that bacteriocins can be safely used.     

面包乳杆菌(Lactobacillus panis)C-M_2细菌素的分离纯化及特性分析

本实验对面包乳杆菌C-M2所产的新型细菌素进行分离纯化和特性研究。通过乙酸乙酯萃取、阳离子交换层析和半制备液相三步分离纯化该细菌素。最终细菌素的比活力达到5 044.96 AU/mg,纯化倍数为79.8倍,但回收率仅为0.35%。通过液相色谱-串联质谱法分析,该细菌素的分子质量为863.52 D,氨基酸序列为MVKKTSAV,它是一种新型的Ⅱ类细菌素。该细菌素具有广泛的抑菌谱,可以抑制革兰氏阳性和阴性的食品腐败菌。该细菌素对热和p H值稳定,即使在121℃灭菌15 min,仍保留82.1%的抑菌活性,在p H 6条件下保留85.6%的抑菌活性。它能被多种蛋白酶失活,不能被脂肪酶和淀粉酶失活,这些结果表明该细菌素具有作为食品生物防腐剂的潜在应用价值。     

Influence of pH and temperature on growth and bacteriocin production by Leuconostoc mesenteroides L124 and Lactobacillus curvatus L442

The aim of this study was to investigate the relationship between the microbial growth, the bacteriocin production and the effect of pH and temperature on the occurrence and the concentration of the maximum activity, to optimize the bacteriocin synthesis during the growth cycle. Two bacteriocins produced by lactic acid strains Leuconostoc mesenteroides L124 and Lactobacillus curvatus L442 were studied. A slight increase of the final biomass resulted in the improvement of the bacteriocin activity in the growth medium under controlled pH (5.0 and 5.5). Temperature and pH had a significant effect on the production of the two bacteriocins and was enhanced by the relatively low growth rates. The optimum production conditions of the bacteriocins did not coincide with those for growth. The optimum pH and temperature values for growth were 6.0-6.5 and 30?°C and for bacteriocin production were 5.5 and 25?°C.     

Development of Wide-Spectrum Hybrid Bacteriocins for Food Biopreservation

The food industry demands new procedures and methods to produce minimally processed, ready to eat food with intact nutritional, taste, and flavor properties. The biopreservation and the use of both bacteriocins produced by lactic acid bacteria (LAB) and bacteriocinogenic strains as an alternative to substitute chemical antimicrobial for food preservation became increasingly important in the last two decades. When the new proposed natural preservatives techniques are applied, probiotics food can be obtained and, simultaneously, foodborne pathogens and spoilage contaminants can diminish. However, bacteriocins produced by LAB have a narrow antibacterial spectrum and are inactive against Gram-negative bacteria like Salmonella and the emergent enterohemorrhagic Escherichia coli. Knowing the mechanism of action and the structural features of microcins synthesized by Gram-negative bacteria and with potent antimicrobial activity against the mentioned microorganism, the proposal is to obtain hybrid peptides (microcin–bacteriocin) with broad antimicrobial spectrum. This review explains how the inability of bacteriocins to cross the outer membrane of Gram-negative bacteria unable them to act on the bacteria. It will also be discussed how a hybrid bacteriocin can be obtained.     

环境胁迫调控植物乳杆菌细菌素合成的研究进展

植物乳杆菌作为具有重要经济价值的乳酸菌被广泛应用于食品发酵与保鲜领域,由于其代谢过程中会产生具有广谱抑菌特性、对热稳定且易被蛋白酶水解的细菌素,因此有作为天然食品生物防腐剂的较大应用潜力。研究表明,在发酵过程中菌体的生长和细菌素的合成受多种环境因素如盐胁迫、酸胁迫、氧胁迫及低高温胁迫的影响,但目前环境因素调节信号分子产生以及调控相关基因合成细菌素的具体机制仍然有待研究,另一方面,通用的调控通路还未被发现。因此,本文介绍了植物乳杆菌抵御胁迫的反应机制并详细阐述了环境胁迫下与细菌素合成密切相关的调控基因和重要调控蛋白,为食品发酵加工过程中合理控制发酵条件,促进细菌素合成从而延长食品货架期提供理论依据。