In vitro study of potentially probiotic lactic acid bacteria strains isolated from kimchi

The objective of the present study was to investigate lactic acid bacteria (LAB) isolated from kimchi for their potential probiotic use. Ten preselected LAB strains were evaluated for their functionality and safety. Examined characteristics included acid and bile tolerance, cell adhesion, antimicrobial activity against pathogens, hemolytic activity, undesirable biochemical characteristics, and antibiotic resistance. Results indicated that consumption of these 10 strains does not pose any health risk, as they were not hemolytic and exhibited no undesirable biochemical activity or antibiotic resistance. In particular, three strains, Lactobacillus plantarum NO1, Pediococcus pentosaceus MP1, and Lactobacillus plantarum AF1, showed high degrees of acid and bile tolerance, adherence to Caco-2 and HT-29 cells, and antimicrobial activity against four pathogens (Staphylococcus aureus, Escherichia coli O157:H7, Salmonella typhi, and Listeria monocytogenes). These results suggest that LAB strains from kimchi may have potential use as novel probiotics.     

Growth studies of potentially probiotic lactic acid bacteria in cereal-based substrates

AIMS: The overall growth kinetics of four potentially probiotic strains (Lactobacillus fermentum, Lact. reuteri, Lact. acidophilus and Lact. plantarum) cultured in malt, barley and wheat media were investigated. The objectives were to identify the main factors influencing the growth and metabolic activity of each strain in association with the cereal substrate. METHODS AND RESULTS: All fermentations were performed without pH control. A logistic-type equation, which included a growth inhibition term, was used to describe the experimental data. In the malt medium, all strains attained high maximum cell populations (8.10-10.11 log10 cfu ml(-1), depending on the strain), probably due to the availability of maltose, sucrose, glucose, fructose (approx. 15 g l(-1) total fermentable sugars) and free amino nitrogen (approx. 80 mg l(-1)). The consumption of sugars during the exponential phase (10-12 h) resulted in the accumulation of lactic acid (1.06-1.99 g l(-1)) and acetic acid (0.29-0.59 g l(-1)), which progressively decreased the pH of the medium. Each strain demonstrated a specific preference for one or more sugars. Since small amounts of sugars were consumed by the end of the exponential phase (17-43%), the decisive growth-limiting factor was probably the pH, which at that time ranged between 3.40 and 3.77 for all of the strains. Analysis of the metabolic products confirmed the heterofermentative or homofermentative nature of the strains used, except in the case of Lact. acidophilus which demonstrated a shift towards the heterofermentative pathway. All strains produced acetic acid during the exponential phase, which could be attributed to the presence of oxygen. Lactobacillus plantarum, Lact. reuteri and Lact. fermentum continued to consume the remaining sugars and accumulate metabolic products in the medium, probably due to energy requirements for cell viability, while Lact. acidophilus entered directly into the decline phase. In the barley and wheat media all strains, especially Lact. acidophilus and Lact. reuteri, attained lower maximum cell populations (7.20-9.43 log10 cfu ml(-1)) than in the malt medium. This could be attributed to the low sugar content (3-4 g l(-1) total fermentable sugar for each medium) and the low free amino nitrogen concentration (15.3-26.6 mg l(-1)). In all fermentations, the microbial growth ceased at pH values (3.73-4.88, depending on the strain) lower than those observed for malt fermentations, which suggests that substrate deficiency in sugars and free amino nitrogen contributed to growth limitation. CONCLUSIONS: The malt medium supported the growth of all strains more than barley and wheat media due to its chemical composition, while Lact. plantarum and Lact. fermentum appeared to be less fastidious and more resistant to acidic conditions than Lact. acidophilus and Lact. reuteri. SIGNIFICANCE AND IMPACT OF THE STUDY: Cereals are suitable substrates for the growth of potentially probiotic lactic acid bacteria.     

Lactic acid bacteria from raw milk as potentially beneficial strains to prevent bovine mastitis

Bovine mastitis produces a wide variety of problems in the dairy farm. The treatment of this disease is based on the use of antibiotics which are not always effective. These drugs are also responsible for the presence of residues in the milk and the increase of antibiotic-resistant strains. Probiotic products were proposed as a valid alternative to antibiotic therapies and are also useful for the prevention of infectious syndromes. With the aim of designing a probiotic product to prevent bovine mastitis, lactic acid bacteria (LAB) were isolated from foremilk samples from different dairy farms in Córdoba-Argentina. One hundred and seventeen LAB were isolated and their beneficial characteristics such as the production of inhibitory substances, surface properties and production of exopolysaccharides (EPS) were assessed. Most of them displayed low degree of hydrophobicity, autoaggregation, EPS negative phenotype and were identified as Enterococcus hirae and Pediococcus pentosaceus. Nine LAB strains inhibited three indicator bacteria. Some isolates were pre-selected and genetically identified according to the results obtained. Antibiotic resistance and virulence factors were studied for the assessment of the safety of the strains. The results obtained were compared to those reported previously from samples obtained in the North-western area of the country and some differences were found.     

Identification and probiotic potential of lactic acid bacteria from camel milk

In the present study, a total of 80 presumed lactic acid bacteria (LAB) were isolated from camel milk. Selected LAB were identified as Lactococcus lactis (cam 12), Enterococcus lactis (cam 14) and Lactobacillus plantarum (cam 15) and their potential were tested by tolerance & de-conjugation of bile salts, antimicrobial activity, surface hydrophobicity and adhesion potential) along with this of probiotics were evaluated for curd formation and assessed for sensory properties and syneresis. Selected LABs showed antimicrobial activity against wide range of pathogenic bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus and Escherchiaia. coli). LAB (cam 12, cam 14 and cam15) were highly sceptible to chloramphenicol, vancomycin, and tetracyclin. In vitro adhesion studies with Caco-2 cells demonstrated strong adhesion activity with hydrophobicity (99%) was observed. Acute oral toxicity of E. lactis and L. plantarum showed non-toxic, non-virulent and safe for industrial application. The study provides potential LAB which may act as a substitute of functional food, synthetic feed and industrial curd formulation with in the shortest span (240 min at 28–32 °C).     

Production of probiotic cabbage juice by lactic acid bacteria

Research was undertaken to determine the suitability of cabbage as a raw material for production of probiotic cabbage juice by lactic acid bacteria (Lactobacillus plantarum C3, Lactobacillus casei A4, and Lactobacillus delbrueckii D7). Cabbage juice was inoculated with a 24-h-old lactic culture and incubated at 30 degrees C. Changes in pH, acidity, sugar content, and viable cell counts during fermentation under controlled conditions were monitored. L. casei, L. delbrueckii, and L. plantarum grew well on cabbage juice and reached nearly 10x10(8) CFU/mL after 48 h of fermentation at 30 degrees C. L. casei, however, produced a smaller amount of titratable acidity expressed as lactic acid than L. delbrueckii or L. plantarum. After 4 weeks of cold storage at 4 degrees C, the viable cell counts of L. plantarum and L. delbrueckii were still 4.1x10(7) and 4.5x10(5) mL(-1), respectively. L. casei did not survive the low pH and high acidity conditions in fermented cabbage juice and lost cell viability completely after 2 weeks of cold storage at 4 degrees C. Fermented cabbage juice could serve as a healthy beverage for vegetarians and lactose-allergic consumers.     

Fermentation of pomegranate juice by probiotic lactic acid bacteria

In this research, production of probiotic pomegranate juice through its fermentation by four strains of lactic acid bacteria: Lactobacillus plantarum, L. delbruekii, L. paracasei, L. acidophilus was examined. Fermentation was carried out at 30°C for 72 h under microaerophilic conditions. Microbial population, pH, titrable acidity, sugar and organic acid metabolism were measured during the fermentation period and the viability of all strains was also determined during the storage time at 4°C within 4 weeks. The results indicated that L. plantarum and L. delbruekii increased the pH sharply at the initial stages of fermentation and the sugar consumption was also higher in comparison with other strains, better microbial growth was also observed for these two strains during fermentation. Citric acid, as a major organic acid in pomegranate juice was significantly consumed by all probiotic lactic acid bacteria. L. plantarum and L. delbruekii showed higher viability during the storage time. Viable cells remained at their maximum level within 2 weeks but decreased dramatically after 4 weeks. Pomegranate juice was proved to be a suitable media for production of a fermented probiotic drink.     

益生乳酸菌遗传稳定性研究进展

益生乳酸菌因为与人类健康息息相关而日益备受关注。时至今日,益生乳酸菌衍生制品已发展成为时尚养生领域的新宠儿。对于准备进入生产流通环节的益生乳酸菌,除需具有优异的益生特性,还应具有良好的稳定性。本文拟从遗传稳定性的研究方法出发,结合其国内外的研究进展作一综述,旨在为同行提供一些参考。     

Boza, a natural source of probiotic lactic acid bacteria

Aims: To evaluate the probiotic properties of strains isolated from boza, a traditional beverage produced from cereals. Methods and Results: The strains survived low pH conditions (pH 3·0), grew well at pH 9·0 and were not inhibited by the presence of 0·3% (w/v) oxbile. Cytotoxicity levels of the bacteriocins, expressed as CC₅₀, ranged from 38 to 3776 μg ml^?1. Bacteriocin bacST284BZ revealed high activity (EC₅₀ = 735 μg ml^?1) against herpes simplex virus type 1. Growth of Mycobacterium tuberculosis was 69% repressed after 5 days in the presence of bacST194BZ. Various levels of auto‐cell aggregation and co‐aggregation with Listeria innocua LMG 13568 were observed. Adhesion of the probiotic strains to HT‐29 cells ranged from 18 to 22%. Conclusions: Boza is a rich source of probiotic lactic acid bacteria. All strains survived conditions simulating the gastrointestinal tract and produced bacteriocins active against a number of pathogens. Adherence to HT‐29 and Caco‐2 cells was within the range reported for Lactobacillus rhamnosus GG, a well‐known probiotic. In addition, the high hydrophobicity readings recorded define the strains as good probiotics. Significance and Impact of the Study: Boza contains a number of different probiotic lactic acid bacteria and could be marketed as a functional food product.     

Isolation and evaluation of probiotic potential of lactic acid bacteria isolated from poultry intestine

The gut is a source of lactic acid bacteria with remarkable functional and technologies properties as well as a potential source of probiotics. In the present study, 13 strains of Lactobacillus were isolated from poultry intestine and identified according to their 16S rDNA sequences, as well as the evaluation of their probiotic potential. The probiotic properties were tested in aspects of antibiotic susceptibility, antimicrobial activity, exopolysaccharide production, lysozyme tolerance, gut condition tolerance (low pH, bile salt tolerance) and adhesion to human colorectal adenocarcinoma cell line (Caco-2). Most isolates were resistance to streptomycin (10 μg/mL), gentamicin (10 μg/mL), kanamycin (30 μg/mL), penicillin (10 μg/mL) and chloramphenicol (30 μg/mL). Isolates shows strong abilities to adhere to Caco-2 cell in the range of (76 to 85%). Isolates SHA101 to SHA113 showed high survival rate under gastrointestinal tract condition (>80%), indicating their potential in application of probiotics. The results of these tests indicate that the lactic acid bacteria isolated from poultry intestine have potential use as probiotic in various products.     

Safety and probiotic functionality of isolated goat milk lactic acid bacteria

Purpose

Lactic acid bacteria (LAB) are traditionally employed in the food industry. LAB strains from goat milk may also present probiotic potential, and it is fundamental to study the safety and functionality aspects which are desirable for their use in food. The objective of this study was to verify the probiotic potential of lactic bacteria isolated from goat milk.

Methods

The presence of safety-related virulence factors (hemolytic activity, gelatinase production, coagulase, and sensitivity to antibiotics) as well as functionality (exopolysaccharide (EPS) production, proteolytic activity, autoaggregation, gas production, survival in the gastrointestinal tract, and antimicrobial activity against bacteria that impair oral health) were determined.

Result

The selected LAB strains are safe against the evaluated parameters and have characteristics of possible probiotic candidates. Especially L. plantarum (DF60Mi) and Lactococcus lactis (DF04Mi) have potential to be added to foods because they have better resistance to simulated gastrointestinal conditions. In addition, they are isolated with already proven antimicrobial activity against Listeria monocytogenes, an important food-borne pathogen. DF60Mi was able to produce EPS (exopolysaccharides). LS2 and DF4Mi strains, both Lactococcus lactis subsp. lactis, demonstrated antimicrobial activity against S. mutans ATCC 25175, a recurrent microorganism in oral pathologies, mainly caries.

Conclusion

This study provides subsidies for future exploration of the potentialities of these LAB strains for both the development of new functional foods and for application in oral health.

     

Potential probiotic properties of lactic acid bacteria isolated from the intestinal mucosa of healthy piglets

In the present study, the probiotic properties of 52 lactic acid bacteria strains, isolated from the intestinal mucosa of 60-day-old healthy piglets, were evaluated in vitro in order to acquire probiotics of potential application. Based on acidic and bile salt resistance, 11 lactic acid bacteria strains were selected, among which 1 was identified as Pediococcus acidilactici, 3 as Enterococcus faecium, 3 as Lactobacillus rhamnosus, 2 as Lactobacillus brevis, and 2 as Lactobacillus plantarum by 16S rRNA gene sequencing. All selected strains were further investigated for transit tolerance in simulated upper gastrointestinal tract, for adhesion capacity to swine intestinal epithelial cells J2 (IPEC-J2), for cell surface characteristics including hydrophobicity, co-aggregation and auto-aggregation, and for antimicrobial activities. Moreover, hemolytic, bile salt hydrolase and biogenic amine-producing abilities were investigated for safety assessment. Two E. faecium (WEI-9 and WEI-10) and one L. plantarum (WEI-51) exhibited good simulated upper gastrointestinal tract tolerance, and showed high auto-aggregation and co-aggregation with Escherichia coli 1570. The strains WEI-9 and WEI-10 demonstrated the highest adherence capacity. The 11 selected strains mentioned above exhibited strong antimicrobial activity against E. coli CVCC1570, Staphylococcus aureus CVCC1882 and Salmonella pullorum AS1.1859. None of the 11 selected strains, except WEI-9 and WEI-33, exhibited bile salt hydrolase, hemolytic or biogenic amine-producing abilities. This work showed that the E. faecium WEI-10 and L. plantarum WEI-51were found to have the probiotic properties required for use as potential probiotics in animal feed supplements.     

阴道中益生特性乳杆菌的分离与功能评价

目的 分离健康女性阴道中的乳杆菌并鉴定其益生特性,为开发治疗妇科疾病的复方益生菌制剂提供新型菌株。方法 采集健康女性阴道分泌物并分离筛选乳杆菌,通过16S rDNA序列分析鉴定乳杆菌分离株,并对其产酸性能、产H2O2能力、抑菌能力、产生物膜能力进行检测。结果 从50名健康女性阴道内共分离出179株乳杆菌,其中卷曲乳杆菌101株、詹氏乳杆菌42株、格氏乳杆菌26株、植物乳杆菌5株、唾液乳杆菌3株以及干酪乳杆菌2株。179株乳杆菌中有146株具有产酸能力,发酵液pH值的最低的5株菌分别为卷曲乳杆菌J3、卷曲乳杆菌J8、詹氏乳杆菌J87,植物乳杆菌J75以及格氏乳杆菌J35,其pH分别为4.20、4.23、4.24、4.26及4.36;产H2O2弱阳性菌株有87株、阳性有37株、强阳性有9株,这9株菌分别为卷曲乳杆菌J3、卷曲乳杆菌J8、卷曲乳杆菌J20、詹氏乳杆菌J87,詹氏乳杆菌J90、詹氏乳杆菌J15、格氏乳杆菌J11、植物乳杆菌J75、植物乳杆菌J69以及植物乳杆菌J40;能拮抗大肠埃希菌的菌株有115株、拮抗金黄色葡萄球菌的有84株、拮抗白假丝酵母的有52株;经统计,对三者同时有拮抗作用且作用最强的只有6株,分别为卷曲乳杆菌J3、卷曲乳杆菌J50、卷曲乳杆菌J62、詹氏乳杆菌J87、詹氏乳杆菌J16和格氏乳杆菌J66;不同乳杆菌产生物膜能力数值范围在1.0~5.4,卷曲乳杆菌、詹氏乳杆菌、干酪乳杆菌的生物被膜形成能力显著高于其他三种菌（P<0.05）。在全部179株菌中,卷曲乳杆菌J3和詹氏乳杆菌J87既具有强的产酸能力和产过氧化氢能力,又有较强抑菌活性,同时产生物膜能力也最强。结论 卷曲乳杆菌J3和詹氏乳杆菌J87具有优良的生物学特性,有望成为用于治疗妇科疾病微生态制剂的备选菌株。     

Screening of species-specific lactic acid bacteria for veal calves multi-strain probiotic adjuncts

The selection of promising specific species of lactic acid bacteria with potential probiotic characteristics is of particular interest in producing multi species-specific probiotic adjuncts in veal calves rearing. The aim of the present work was to select and evaluate in?vitro the functional activity of lactic acid bacteria, Bifidobacterium longum and Bacillus coagulans strains isolated from veal calves in order to assess their potential use as multi species-specific probiotics for veal calves. For this purpose, bacterial strains isolated from faeces collected from 40 healthy 50-day-calves, were identified by RiboPrinter and 16s rRNA gene sequence. The most frequent strains belonged to the species B. longum, Streptococcus bovis, Lactobacillus animalis and Streptococcus macedonicus. Among these, 7 strains were chosen for testing their probiotic characteristics in?vitro. Three strains, namely L. animalis SB310, Lactobacillus paracasei subsp. paracasei SB137 and B. coagulans SB117 showed varying individual but promising capabilities to survive in the gastrointestinal tract, to adhere, to produce antimicrobial compounds. These three selected species-specific bacteria demonstrated in?vitro, both singularly and mixed, the functional properties needed for their use as potential probiotics in veal calves.     

圈养大熊猫肠道乳酸菌分离及益生特性

【背景】大熊猫数量稀少、繁殖困难,在其生长过程中极易感染消化系统疾病甚至死亡。【目的】分析圈养大熊猫肠道可培养乳酸菌的群落结构与功能,筛选具有益生特性的乳酸菌菌株,为大熊猫消化系统疾病的预防和肠道微生物研究提供理论参考及菌种资源。【方法】采用3种培养基分离大熊猫粪便中的乳酸菌,通过革兰氏染色镜检和过氧化氢试验对分离的菌株进行初步鉴定,基于BOXA1R-PCR图谱遗传多样性选取代表菌株进行16S rRNA基因测序分析并进行主成分分析(principal component analysis, PCA),同时分析乳酸菌菌株安全性和益生特性。【结果】通过初步鉴定共分离获得58株乳酸菌,根据BOXA1R-PCR结果挑选20株菌进行测序,结果显示20株菌分属于明串珠菌属(Leuconostoc)、肠球菌属(Enterococcus)、魏斯氏菌属(Weissella)和链球菌属(Streptococcus)这4个属,主成分分析结果表明不同年龄段的大熊猫肠道乳酸菌群落结构存在差异。20株乳酸菌均不溶血,17株乳酸菌对11种抗生素均敏感;11株菌耐pH值2.0酸性条件,14株菌对0.3%的胆盐具有良好...     

降解嘌呤核苷乳酸菌的筛选及益生特性探索

【背景】高尿酸血症是人体内嘌呤代谢紊乱导致的一种慢性代谢疾病,利用乳酸菌降解嘌呤类物质是辅助治疗高尿酸血症的新方法。【目的】筛选高效降解嘌呤核苷的乳酸菌并对其益生特性进行研究。【方法】利用HPLC法评价乳酸菌对肌苷、鸟苷的降解效果。通过药敏性试验、体外耐受性试验及细胞黏附试验研究目标菌株的益生特性。【结果】筛选出一株发酵乳杆菌(Lactobacillus fermentum) SR2-6,对肌苷和鸟苷的降解率分别为99.26%和98.85%。该菌株对青霉素、氯霉素等5种常见抗生素不具备耐药性,在pH 2.0环境下处理4 h后菌株的存活率为76.51%,在饱腹状态下的人工肠液模拟消化4 h后活菌数仍能达到6.85 lg (CFU/mL),对Caco-2细胞的黏附数为(52.29±15.14) CFU/cell。【结论】发酵乳杆菌SR2-6能够高效降解肌苷和鸟苷且具有优良的益生特性,是预防和治疗高尿酸血症的潜在优势菌株,可作为优势菌种资源应用于相关功能产品的开发。     

Mitogenic response and probiotic characteristics of lactic acid bacteria isolated from indigenously pickled vegetables and fermented beverages

Lactic acid bacteria from indigenous pickled vegetables and fermented beverages (fermented rice and Madhuca longifolia flowers) were isolated and investigated for their functional characteristics in vitro as potential new probiotic strains. Four isolates (all Lactobacillus spp.) selected on the basis of high tolerance to bile (0.2%) were identified by standard and molecular methods (16S rDNA) as L. helveticus, L. casei, L. delbrueckii and L. bulgaricus from pickled vegetables and fermented beverages respectively. These selected strains had antibiotic resistance, tolerance to artificial gastric juice and phenol (0.4%), enzymatic profile, and antagonistic activity against enteric pathogens (Enterobacter sakazakii, Salmonella typhimurium, Shigella flexneri 2a, Listeria monocytogenes, Yersinia enterocolitica and Aeromonas hydrophila). All strains survived well in artificial gastric juice at low pH (3.0) values for 4 h, possessed bile salt hydrolase activity and were susceptible to most antibiotics including vancomycin. Additionally, the isolates exhibited high tolerance to phenol, high cell surface hydrophobicity (>60%) and induced proliferation of murine splenocytes. All the four strains of present study suppressed the Con A-stimulated proliferation of the mouse spleen cells, although L. casei had the strongest suppressive effect. The results of this study suggest a potential application of the strains (following human clinical trials), for developing probiotic foods.     

Updating the importance of lactic acid bacteria in fish farming: natural occurrence and probiotic treatments

Many recent papers have deepened the state of knowledge about lactic acid bacteria (LAB) in fish gut. In spite of high variability in fish microbiota, LAB are sometimes abundant in the intestine, notably in freshwater fish. Several strains of Streptococcus are pathogenic to fish. Streptococcus iniae and Lactococcus garvieae are major fish pathogens, against which commercial vaccines are available. Fortunately, most LAB are harmless, and some strains have been reported for beneficial effects on fish health. A major step forward in recent years was the converging evidence that LAB can stimulate the immune system in fish. An open question is whether viability can affect immunostimulation. The issue is crucial to commercialize live probiotics rather than inactivated preparations or extracts. There has been a regain of interest in allochthonous strains used as probiotics for terrestrial animals or humans, due to economical and regulatory constraints, but the short survival in sea water may limit application to marine fish. If viability is required, alternative treatments may include the incorporation of prebiotics in feed, and other dietary manipulations that could promote intestinal LAB. Antagonism to pathogens is the other main feature of candidate probiotics, and there are many reports concerning mainly carnobacteria and Enterococcus. Some bacteriocins were characterized which may be of interest not only for aquaculture, but also for food preservation.