Potential applications of lactic acid bacteria and bacteriocins in antimycobacterial therapy

Tuberculosis(TB) is a communicable disease caused by Mycobacterium tuberculosis(M. tuberculosis). WHO estimated that 10.4 million new(incident) TB cases worldwide in year 2016. The increased prevalence of drug resistant strains and side effects associated with the current anti-tubercular drugs make the treatment options more complicated. Hence, there are necessities to identify new drug candidates to fight against various sub-populations of M. tuberculosis with less or no toxicity/side effects and shorter treatment duration. Bacteriocins produced by lactic acid bacteria(LAB) attract attention of researchers because of its "Generally recognized as safe" status. LAB and its bacteriocins possess an effective antimicrobial activity against various bacteria and fungi. Interestingly bacteriocins such as nisin and lacticin 3147 have shown antimycobacterial activity in vitro. As probiotics, LAB plays a vital role in promoting various health benefits including ability to modulate immune response against various infectious diseases. LAB and its metabolic products activate immune system and thereby limiting the M. tuberculosis pathogenesis. The protein and peptide engineering techniques paved the ways to obtain hybrid bacteriocin derivatives from the known peptide sequence of existing bacteriocin. In this review, we focus on the antimycobacterial property and immunomodulatory role of LAB and its metabolic products. Techniques for large scale synthesis of potential bacteriocin with multifunctional activity and enhanced stability are also discussed.

Isolation and Characterization of Lactic Acid Bacteria Producing Bacteriocin like Inhibitory Substance (BLIS) from “Gappal”, a Dairy Product from Burkina Faso

Indigenous fermented foods are known for their nutritional and functional properties but they are often spoiled by pathogenic bacteria that can constitute a food safety problem. “Gappal” is a no-thermal treat food based on millet dough and milk and its production conditions can constitute a food safety problem. The aim of this study was to screen and identify LAB producing Bacteriocin-like inhibitory substances using a matrix similar to “Gappal”. The detection of potential BLIS was first performed using overlaid method after enrichment of samples in whey and millet dough. The isolates demonstrating inhibiting area were preselected, purified and tested for the presence of antibacterial properties using their neutralized cell-free culture supernatant and subsequently treated with catalase in combination with protease, pepsin or trypsin. The antimicrobial effect of two isolates (Gbf48 and Gbf50) after growth on MRS broth over 12 h at 30?C were active against E. faecalis ATCC 19433, M. luteus ATCC 49732, S. aureus ATCC 2523, L. monocytogenes, B. megaterium, B. sphaericus and B. cereus with an activity of 2560 AU/mL. The 16S RNA gene sequencing identification indicated that these isolates are Pediococcus acidilactici. Gbf 48 and Gbf 50 could be used to improve preservative factors for a controlled fermentation of non thermal treatment fermented food for their potential of acidification adds to BLIS production.

Partial Characterization of Bacteriocins from Two <i>Pediococcus acidilactici</i>Strains Isolated during Traditional Sorghum Beer Processing in Côte d’Ivoire

Two lactic acid bacteria strains (At1BEAE22 and At344E21) isolated during tchapalo production were identified on the basis of phenotypic analyses. Bacteriocins produced by these strains were tested for their antimicrobial activities using well diffusion agar method. Heat resistance, pH sensitivity and enzyme treatments were also analyzed. Results showed that both lactic acid bacteria strains were identified as Pediococcus acidilactici. Their bacteriocins inhibited growth of Lactobacillus delbrueckii F/31, Listeria innocua ATCC 33090, Enterococcus faecalis, Enterococcus faecalis ATCC 29212, Streptococcus sp, Enterococcus faecalis CIP 105042 and Enterococcus faecium ATCC 51558. These bacteriocins were heat stable at 60&degC for 30 min for all indicator bacteria. However, they remained active only against Lactobacillus delbrueckii and Listeria innocua at 121&degC for 60 min. Moreover, they were active in a wide range of pH (3 to 9) with a maximum activity observed at pH 5 and 6 on all indicator bacteria. But, bacteriocin from Pediococcus acidilactici At34E21 was more stable at acidic pH than basic one. The fact that the bacteriocin was inactivated by proteinase K and α-chymotrypsin indicated its proteinaceous nature, a general characteristics of bacteriocins.

Study Bacteriocin Production and Optimization Using New Isolates of <i>Lactobacillus</i>spp. Isolated from Some Dairy Products under Different Culture Conditions

Lactobacilli belong to the group of lactic acid bacteria (LAB), that have several distinguished abilities such as production of lactic acid, enzymes such as β-Galactosidase and natural antimicrobial substances called bacteriocins. Bacteriocin is a biopreservative agent potential of suppressing growth of some contaminant bacteria in food industry but its commercial availability is limited and costly. The study aimed to select isolates of Lactobacillus spp. potential for producing bacteriocins to suppress the growth of Escherichia coli ATCC 25922 and Bacillus subtilis NCIB3610, and to optimize the process of bacteriocin production. Results obtained in this study showed that L. acidophilus isolate CH1 was selected as the best candidate for bacteriocin among the four isolates that tested. The largest amounts of the bacteriocins were synthesized only in MRS medium was supplemented with K2HPO4 (1.0%), Tween 80 (1%), Beef extract (1%), glucose, cyctein and peptone extract (1%). The optimization of culture conditions for bacteriocin production areas showed that corn steep liquor medium was the best medium for all isolates against Bacillus subtilis while no effect was observed on Escherichia coli ATCC 25922 except when used MRS medium. The optimum conditions for bacteriocin production were pH 6.0, temperature 34?C with 4% Phenyl acetamide showing the greatest growth inhibition areas.

Use of Bacteriocin Producing <i>Lactococcus lactis</i>subsp. <i>lactis</i>LABW4 to Prevent <i>Listeria monocytogenes</i>Induced Spoilage of Meat

A bacteriocin producing strain of Lactococcus lactis subsp. lactis LABW4 was isolated from naturally fermented milk product which exhibited strong antibacterial activity against Listeria monocytogenes MTCC657, a food spoilage psychrophilic organism. Both cell free and heat killed supernatants of LABW4 were effective to produce zones of inhibition against L. monocytogenes in vitro. The antibacterial metabolite(s) of LABW4 showed strong cidal effect on the growth of L. monocytogenes. Meat samples, mixed with heat killed supernatant of LABW4 when inoculated with Listeria, remain fresh up to 25 days in refrigerated condition whereas spoilage started immediately after 24 hours of inoculation for control sets. Enhancement of Lactate dehydrogenase of L. monocytogenes upon treatment with LABW4 cell free supernatant suggested its lytic mode of action. Cell lysis or degradations were also supported by scanning electron micrograph of treated cells.

传统发酵乳品中产广谱细菌素乳酸菌选育

为选育产广谱细菌素乳酸菌,采用琼脂扩散法对甘肃牧区传统发酵乳品中分离纯化的96株乳酸菌进行了筛选,并确定产细菌素菌株,具有最佳抑菌效果的菌株经重离子束12C6+辐照诱变,再采用培养皿分区法进行6种指示菌广谱抑菌性能比较。结果表明,琼脂扩散法筛选出抑菌效果最佳的产细菌素菌株Lp1,经辐照诱变得到98株突变菌,选育出对大肠埃希氏菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)、单核细胞增生李斯特氏菌(Listeria monocytogenes)、沙门氏菌(Salmonella)、志贺氏菌(Shigella)和克罗诺杆菌(Cronobacter)抑菌性能均明显优于出发菌株Lp1的5株突变株L088、L087、L063、L049、L010进行广谱抑菌试验,其中菌株L088和L063为广谱抑菌性能较好菌株,突变株L088对上述6种指示菌的抑菌扇环半径比出发菌株Lp1抑菌扇环半径分别提高47.81%、33.28%、22.97%、45.25%、21.39%、40.21%,突变株L063对上述6种指示菌的抑菌扇环半径比出发菌株Lp1抑菌扇环半径分别提高54.27%、29.18%、25.37%、58.03%、17.85%、42.13%。采用培养皿分区法可同时在1个培养皿中完成检测6种指示菌的抑菌试验,可高效筛选产广谱细菌素乳酸菌。

高光纯D-乳酸生产菌株假肠膜明串珠菌HL64-1的分离鉴定及其发酵特性

从自然界中筛选分离产酸菌是获得高光学纯度乳酸生产菌株有效的途径之一。从腐烂果实中分离获得一株产高光学纯度D-乳酸菌株HL64-1,经形态学、16S rDNA序列分析、序列相似性Blast比对分析鉴定为假肠膜明串珠菌(Leuconostoc pseudomesenteroides)。在基础发酵培养基中摇瓶发酵24 h,产D-乳酸的量达到62.18 g/L,产酸速率达2.59 g/(L·h),光学纯度达99.90%(ee);在5 L发酵罐中放大培养,通过补加碳源,发酵72 h,D-乳酸产量达到78.74 g/L,平均产酸速率达1.09 g/(L·h)。该菌株可以有效利用农业副产物花生饼粉和棉籽粉作为替代氮源以降低发酵原料成本。该菌还可利用木糖产生D-乳酸,且葡萄糖能显著提高木糖的利用效率,极具工业应用前景。

LuxS/AI-2群体感应系统在乳酸菌细菌素合成中的作用

乳酸菌细菌素具有抑菌谱广、稳定性高、安全性高等优势,作为新型生物防腐剂备受青睐,但目前工业化应用的细菌素数量有限,合成量低是其应用受限的重要原因。国内外研究显示与特定的微生物共培养是提高乳酸菌细菌素合成量的有效方法,该过程受到LuxS/AI-2群体感应系统的调控。文章从乳酸菌LuxS/AI-2群体感应系统的组成及LuxS/AI-2群体感应系统在乳酸菌细菌素合成中的作用两个方面进行论述,为乳酸菌细菌素合成量的提高和工业化应用的实现提供了一定的理论依据。

基于文献计量的乳酸菌细菌素研究进展分析

乳酸菌细菌素是乳酸菌在代谢过程中产生的一类具有抑菌活性的天然蛋白质或多肽类物质,具有无抗药性、可生物降解、抑菌效果好等优点,在食品、医药、饲料领域应用前景广阔。本文基于文献计量学方法,检索2000~2023年CNKI数据库和Web of Science(WOS)核心合集有关乳酸菌细菌素领域的文献,得到627篇中文文献和2543篇英文文献。使用CiteSpace软件从年度发文量,发文国家、作者、机构和期刊,高被引文献,关键词共现聚类等角度分析该领域的研究现状和热点。结果显示:2000~2022年发文量总体呈上升的趋势。西班牙、印度、中国的发文量在国家排行前三。CNKI数据库与WOS数据库发文量最高的作者分别是中国农业大学李平兰和巴西圣保罗大学Todorov SD。发文量最高的期刊分别是《食品工业科技》与《Journal of Appled Micbiogy》。CNKI数据库中关键词分析可以看出,文章多是从不同食品样本中分离、筛选、鉴定获得产细菌素的乳酸菌,进一步评价细菌素的抑菌活性,并探讨其在食品行业中的应用;突现词分析表明细菌素抑菌机制、细菌素与益生菌的联系是目前研究热点。WOS数据库中关键词“胃肠道”、“基因特征”、“单增核李斯特菌”、“抑菌活性”出现频次较高,主要热点是抑制抗生素耐药细菌的乳酸菌细菌素的挖掘及其基因特征的解析。通过文献综合分析,为我国科研人员从事相关研究和预测行业未来发展趋势提供参考和帮助。

产细菌素海洋乳酸菌的筛选及细菌素抑菌机制

【目的】筛选海洋源产细菌素乳酸菌,探讨细菌素抑菌机制。【方法】从市售海鱼的肠道中筛选出一株对金黄色葡萄球菌(Staphylococcus aureus)和大肠埃希菌(Escherichia coli)有较强抑菌效果的菌株GOFEL226,通过16S rDNA序列鉴定乳酸菌,用乙酸乙酯提取细菌素,利用分光光度法、电导率法、扫描电镜技术探究细菌素的抑菌机制。【结果】菌株GOFEL226为戊糖乳植物杆菌(Lactiplantibacillus pentosus),GFEB226细菌素对金黄色葡萄球菌和大肠埃希菌的最小抑菌质量浓度为0.883 mg/mL;其对指示菌的生长有明显的抑制作用,可导致细胞的蛋白质、核苷酸、带电离子泄漏到细胞外,对细胞膜具有破坏作用。【结论】GFEB226细菌素可通过破坏革兰阳性和革兰阴性菌的细胞膜,使其胞内物质泄漏到胞外,进而导致细胞的死亡。

抗奶牛乳房炎主要病原菌细菌素的筛选及其生物学特性分析

为了筛选出对奶牛乳房炎主要病原菌具有抑菌活性的细菌素,并对其生物学特性进行分析。本试验采用涂布和平板划线方法从吉林市传统辣白菜中分离纯化乳酸菌,并以金黄色葡萄球菌为指示菌通过琼脂扩散法进行抑菌试验,同时结合排酸和排过氧化氢试验初步筛选出拮抗菌株。通过菌株形态学特征和16S rRNA序列分析鉴定拮抗菌株。测定菌株生长和抑菌动力学曲线确定最佳发酵时间。采用蛋白酶敏感性、热稳定性和酸碱稳定性试验测定抗菌活性物质的理化特性,并测定其抑菌谱。结果显示,本试验分离出1株可产细菌素的拮抗菌株MX1,经鉴定其为植物乳杆菌,最佳发酵时间为22 h;MX1菌株分泌的细菌素具有良好的热稳定性和酸稳定性,经高温处理2 h或处于pH为3.0和4.0等酸性较强的环境下仍能保持较强的抗菌活性;MX1菌株分泌的细菌素对奶牛乳房炎主要致病菌金黄色葡萄球菌、大肠杆菌和肺炎克雷伯菌具有良好的抗菌活性。结果表明,本试验筛选获得的细菌素有望作为替抗产品用于细菌性奶牛乳房炎的防治。

Recent biotechnological trends in lactic acid bacterial fermentation for food processing industries

Lactic acid bacteria(LAB)are non-mobile,gram-positive,non-spore-forming,micro-aerophilic microorganisms widely explored as starter cultures food industry to enhance the gustatory,nutritional value,imparts appetizing favour,texture to milk,vegetative,meat foods and prolongs their shelf life.This vast review emphasis various LABs widely explored in the food industry.Herein,we have summarized the classifcation of LAB strains,their metabolic pathways for biosynthesis of lactic acid,ethanol,acetic acid and demonstrated their application in various food industries for making fermented milk(yoghurt),cheese,beverages,bread,and animal foods.The wide spectrum of LAB-based probiotics,bacteriocins,exopolysaccharides,bio preservative and their relevant benefts towards human health has also been discussed.Moreover,LAB bacteriocins and probiotics in food application may limit the growth of pathogenic,while boosting health immunity.Microbial exopolysaccharides have interesting characteristics for the fermented food industry as new functional foods.Later on,we have discussed the various advancement in metabolic engineering,synthetic biology tools,which have gained considerable interest to elucidate the biosynthetic pathway for tailoring cellular metabolism for high activity.

一株乳酸菌产类细菌素Enteriocin LK-S1的初步研究

从鸡肠道分离的 5 9株乳酸菌中 ,筛选出一株产类细菌素的乳酸菌 ,编号为SE - 81.初步鉴定为肠球菌属 (Enterococcus) .在排除有机酸和过氧化氢的干扰作用后 ,SE - 81菌株对溶壁微球菌(Micrococcuslysodeikticus)、金黄色葡萄球菌 (Staphylococcusaureus)和枯草杆菌 (Bacillussubtilis)等革兰氏阳性菌和大肠杆菌 (Escherichiacoli)及鼠伤寒沙门氏菌 (Salmonellatyphimurium)等革兰氏阴性菌有强烈的抑制作用 .用胰蛋白酶处理发酵上清液后 ,抑菌活性丧失 .因此初步认为该菌株产生一类具有广谱抑菌活性的类细菌素物质 ,命名为EnteriocinLK -S1.它具有较广的抗菌谱 ,作用pH在 4 .0～ 6 .0 ,有很好的热稳定性 .

产细菌素乳酸菌的筛选及鉴定

从传统发酵制品中分离筛选到50株乳酸菌,通过琼脂扩散法从中筛选出5株对指示菌具有明显抑菌作用的菌株,通过排除酸和过氧化氢的作用后,其中一株菌仍具有一定的抑菌活性。用胰蛋白酶对其发酵液进行处理后,活性下降很大,说明代谢产物中含有蛋白性质的抑菌物质,可能是细菌素。对此菌株进行鉴定,初步认为是戊糖乳杆菌,并对其生长能力和产酸能力进行了测定。

乳酸菌的细菌素及乳链菌肽在食品工业中的发酵与应用

乳酸菌的细菌素是具有抗菌活性的多肽、蛋白质或蛋白质复合物 ,其中乳链菌肽是一种广泛应用的高效、无毒的天然食品防腐剂。

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。

乳酸菌素的研究现状和发展趋势

乳酸菌素是由乳酸菌产生的一种具有活性的多肽或蛋白质物质,大部分细菌素对近缘关系的细菌有抑制作用,少数细菌素抑菌谱很广。主要可分为热稳定的小分子肽,热敏感的大分子蛋白和羊毛硫抗生素。乳酸菌素是一种纯乳酸菌产生的制剂,是将脱脂乳经杀菌、真空浓缩,再经乳酸菌发酵后干燥而制成的乳酸菌体及其代谢产物混价粉状物,可作医药用或食品添加剂,属疗效型乳制品。本文对乳酸菌素的分类、抑菌机理及在食品和医药方面的应用作了全面系统的综述,并指出了今后的研究方向和应用前景。

猪源产细菌素乳酸菌的抑菌产物特性研究

对 R- 2 1- 1、R- 2 1- 3、R- 17- 3三株来自猪肠道的能够抑制大肠杆菌的乳酸菌所产生的抑菌物质进行了部分理化特性的考察 ,发现其对蛋白酶敏感 ,排除酸后仍有抑菌活性存在 ,初步判断其中含有细菌素。三株菌的发酵上清液分别用 70℃和 10 0℃ (30 m in)、12 1℃ (15 m in)处理后 ,仍然分别保持有 84%、84%、91.6 %以上抑菌活性 。

1株产细菌素乳酸菌的筛选和鉴定

目的从植物性材料中筛选产细菌素的乳酸菌。方法琼脂扩散法。结果所筛选的产细菌素R 260菌株经鉴定为植物乳杆菌。排除有机酸、过氧化氢等干扰因素后,发酵液仍有很强的抑菌作用;用胰蛋白酶和胃蛋白酶处理后,发酵液抑菌活性急剧下降,因而确定产生的抑菌物质具有蛋白质性质,是一种细菌素。抑菌谱试验测定表明,此菌株的发酵液不仅抑制革兰阳性菌,而且对部分革兰阴性菌也有抑制作用,因此产生的是一类广谱细菌素。结论筛选到了1株产广谱细菌素的乳酸菌。

产细菌素乳酸菌筛选方法的研究进展

近年来新型的乳酸菌细菌素不断出现,而对这类乳酸菌的筛选方法也从传统的平板筛选法,逐渐向基于生物信息学的高通量、快速筛选模式发展。文中比较了琼脂扩散法、比浊微孔板生物测定法、生物荧光法、基于PCR方法的快速筛选等方法的优缺点以及产细菌素乳酸菌的快速筛选策略,期望对新型乳酸菌细菌素的开发和利用提供新思路。