Diversity Of Lactic Acid Bacteria Research Articles

In vitro characterization of lactic acid bacteria from Indian fermented rice for probiotic applications

AimTo investigate probiotic attributes of lactic acid bacteria (LAB) isolated from under-explored Indian fermented rice for potential application in consumer health and functional product development. Methods and resultsThe isolates endured conditions resembling gastric stress, including pH (3), bile salt (4%), NaCl (6%), and phenol (0.6%). The selected isolates were identified as L. fermentum and L. plantarum strains by 16 S rRNA sequencing. In a simulated gastrointestinal tract (GIT), isolate SR1 outperformed other cultures in terms of viability. Auto-aggregation, and mucin adhesion abilities were tested for colonization potential. In which, compared to other isolates, MCR1 showed greater mucin adherence. SR1 and MCR1 showed higher percentages of auto-aggregation than GG. The auto-aggregation ranged from 9% to 88%., the levels significantly increase after 24 h incubation. The lower Salt aggregation Test (SAT) values indicated efficient hydrophobicity necessary for persistence in GIT and competitive inhibition to pathogens. All the isolates displayed considerably higher galactosidase activity than GG, isolate FCR2 expressed the highest, up to 613±0.92 Miller’s unit/ml activity. The probiotic candidates displayed broad spectrum antimicrobial activity against food-spoilage fungi and entero-pathogens. The study of safety aspects such as hemolytic, DNase activity, antibiotic susceptibility confirmed unavailability of any virulent factor. ConclusionThe isolates developed substantial galactosidase activity and significant broad-spectrum antibacterial activity. These characteristics make isolates an effective commercial option for β-galactosidase production in the food sector to create low-lactose or lactose-free products. Overall, the isolates' capacity for survival, colonization, and other useful traits may be of commercial relevance. Additionally, isolates can be researched for the production of antibacterial agents and in vivo studies for development of future functional food products. Moreover, these findings lay a robust groundwork for future exploration in probiotics, functional foods and nutraceuticals, while also shedding light on the mechanisms underlying the health benefits of the specified traditional food source. SignificanceThis investigation uncovered potential probiotic LAB of Indian fermented rice origin. By doing so, it expands our understanding of LAB diversity and presents promising candidates for applications in gut health improvement, functional food development, and exploration of natural antibacterial solutions.

Evaluation of the performance of a three-strains lactic acid bacteria cocktail for the control of Listeria monocytogenes on marinated lean pork

The aim of this study was to evaluate the addition of a cocktail of three lactic acid bacteria (LAB) (Lactococcus lactis, Lacticaseibacillus paracasei and Lactiplantibacillus plantarum) as a protective culture into marinated pork. The pork was artificially inoculated with two Listeria monocytogenes strains and stored for 12 days. Two packagings were used: vacuum or modified atmosphere packaging (MAP). LAB, L. monocytogenes, psychrotrophic bacteria, pH, aw, color, the metataxonomic profile and the sensorial quality of the product were evaluated. The growth of L. monocytogenes under vacuum and MAP was reduced with the use of the LAB up to 0.8 and 0.7 log10 CFU/g, respectively. LAB counts gradually increased, which was accompanied by a slight decrease in pH. In LAB samples, psychrotrophic bacteria showed a reduction at day 12 as compared to non-inoculated samples. Some minor differences were also observed among samples for color and sensory parameters. Regardless of the type of packaging, the microbiota of the marinated pork was dominated initially by Photobacterium and subsequently during storage by a diversity of LAB. The application of LAB could help to obtain a safe product, although further evaluation would be required to optimize the application of the LAB cocktail in real-scale commercial scenarios.

Fungal-Bacterial Mutualism: Species and Strain-Dependent Simultaneous Modulation of Branched-Chain Esters and Indole Derivatives in Fermented Sausages through Metabolite Cross-Feeding.

The precise impact of species and strain diversity on fungal-bacterial interactions and the overall community functioning has remained unclear. First, our study revealed how Debaryomyces hansenii influences diverse bacteria to accumulate key metabolites in a simulated fermented food system. For flavor, D. hansenii promoted the accumulation of branched-chain esters in Staphylococcus xylosus by promoting growth and facilitating the precursor branched-chain acids transformations but hindered the accumulation of Staphylococcus equorum. Furthermore, fungal-bacterial interactions displayed diversity among S. equorum strains. For bioactive compounds, species and strain diversity of lactic acid bacteria (LAB) also influences the production of indole derivatives. Then, we investigated specific metabolic exchanges under reciprocal interaction. Amino acids, rather than vitamins, were identified as the primary drivers of the bacterial growth promotion. Moreover, precursor transformations by D. hansenii played a significant role in branched-chain esters production. Finally, a synthetic community capable of producing high concentrations of branched-chain esters and indole derivatives was successfully constructed. These results provide valuable insights into understanding and designing synthetic communities for fermented sausages.

Prebiotic Effect of Cogon Grass Root Extract on Stimulating Lactic Acid Bacteria Growth in Mice Intestine

Lactic acid bacteria (LAB) are known for their numerous beneficial effects for health and their colonization within intestines is affected by prebiotic consumption. Cogon grass root is an herbal medicine which contain substantial quantities of polyphenols. Recently, many studies suggested polyphenols as a novel group of prebiotics. Therefore, this study aimed to explore prebiotic effect of cogon grass root extract (CGRE) on stimulating growth of LAB in mice intestine. Mice (n =7/group) were divided into three groups; group A (control), group B and C received CGRE orally with daily dosage 90 and 115mg/kg BW, respectively. After 14 days of treatment, all mice were sacrificed. LAB was isolated and counted from ileum. Additional biochemical tests were performed to confirm the bacteria as LAB. Further identification of representatives LAB was performed with API-CHL-50 System. We found increased growth and diversity of LAB in the treatment group with optimum growth stimulation at CGRE dosage 90mg/KgBW daily (group B). Further identification showed Lactococcus lactis was the most frequent LAB found in all groups, with additional Lactobacillus paracasei and Lactobacillus curvatus were found in the treatment group. These findings support additional benefit of CGRE as prebiotics by stimulating LAB growth and diversity in mice intestine.

Genetic Identification and Technological Potential of Indigenous Lactic Acid Bacteria Isolated from Alheira, a Traditional Portuguese Sausage.

Alheira is a naturally fermented meat sausage traditionally made in the Portuguese region of Trás-os-Montes. Lactic acid bacteria (LAB) are the dominant microorganisms in alheira and can endow it with various technological properties. This study aimed (1) to characterize technological features and in vitro antimicrobial activity of LAB isolated from alheira, and (2) to reveal associations between such phenotypic characteristics and the isolates species identified through amplification and sequencing of the 16S ribosomal gene. Sixty-two LAB isolates were identified and Enterococcus (E.) faecium corresponded to 32.3% of isolates, followed by Leuconostoc (L.) mesenteroides (19.4%) and Latilactobacillus (Lb.) sakei (17.7%), aligning with previous research on traditional Portuguese fermented meat sausages. The phenotypic analysis of LAB isolates indicated diverse acidification capacities, proteolytic activities, and inhibitory effects against foodborne pathogens Listeria (L.) monocytogenes, Salmonella (S.) Typhimurium and Staphylococcus (S.) aureus. Overall, lactobacilli displayed high inhibition activity against the pathogens S. aureus, L. monocytogenes, and S. Typhimurium. Although the mechanisms for the inhibition of pathogen growth need to be further elucidated, these findings enhance our understanding of LAB diversity and functionality in alheira sausages, contributing to product safety and quality.

Microbial characterization of Sichuan Baoning vinegar: lactic acid bacteria, acetic acid bacteria and yeasts.

Sichuan Baoning vinegar, a typical representative of Sichuan bran vinegar, is a famous traditional fermented food made from cereals in China. At present, there are few studies on microbial characterization of culturable microorganisms in solid-state fermentation of Sichuan bran vinegar. To comprehensively understand the diversity of lactic acid bacteria, acetic acid bacteria and yeasts, which play an important role in the fermentation of Sichuan bran vinegar, traditional culture-dependent methods combined with morphological, biochemical, and molecular identification techniques were employed to screen and identify these isolates. A total of 34 lactic acid bacteria isolates, 39 acetic acid bacteria isolates, and 48 yeast isolates were obtained. Lactic acid bacteria were dominated by Enterococcus durans, Leuconostoc citreum, Lactococcus lactis, and Lactiplantibacillus plantarum, respectively. Latilactobacillus sakei was the first discovery in cereal vinegar. Acetic acid bacteria were mainly Acetobacter pomorum and A. pasteurianus. The dominant yeast isolates were Saccharomyces cerevisiae, in addition to four non-Saccharomyces yeasts. DNA fingerprinting revealed that isolates belonging to the same species exhibited intraspecific diversity, and there were differences between phenotypic and genotypic classification results. This study further enriches studies on cereal vinegar and lays a foundation for the development of vinegar starters.

Exploring the influence of garlic on microbial diversity and metabolite dynamics during kimchi fermentation

Garlic (Allium sativum) is a key ingredient in Korean cuisine, particularly in the preparation of kimchi, contributing to its flavor and taste. Garlic has been a potential resource for lactic acid bacteria (LAB) in kimchi. However, the mechanism by which it influences microbial diversity and metabolite production is unclear. This study investigated the effect of garlic on the bacterial composition of and metabolite changes in kimchi. To achieve this, four separate batches of kimchi were prepared with varying garlic concentrations (w/w): 0 %, 1 %, 2 %, and 4 %, and the bacterial communities and metabolite production were monitored. In the early stages of fermentation, the count of LAB, operational taxonomic units (OTUs), and Shannon index increased linearly with the increase in garlic content. This indicated that garlic is a rich resource and contributes to the diversity of LAB during kimchi fermentation. Compared with the kimchi samples with a lower garlic content, those with a high garlic content (≥2 %) exhibited increased abundance of Lactobacillus and Leuconostoc as well as noticeable differences in functional diversity, including carbohydrate, amino acid, and energy metabolisms. Correlation analysis between sugars, organic acids, and predominant LAB in the garlic-containing kimchi samples suggested that in kimchi samples with high garlic content, LAB played a significant role in the fermentation process by metabolizing sugars and producing organic acids. Overall, this study demonstrated that the addition of garlic has a positive impact on the bacterial diversity and metabolite production during kimchi fermentation, potentially affecting the fermentation process and flavor profile of kimchi.

Selection and evaluation of lactic acid bacteria from chicken feces in Thailand as potential probiotics.

Lactic acid bacteria (LAB) are widely used as probiotics in poultry production due to their resilience to low pH and high bile salt concentrations, as well as their beneficial effects on growth performance and antagonistic activity against enteric pathogens. However, the efficacy of probiotics depends on strain selection and their ability to colonize the host's intestine. This study aimed to select, identify, and evaluate LAB strains isolated from chicken feces in Thailand for potential use as probiotics in the chicken industry. LAB strains were isolated from 58 pooled fresh fecal samples collected from chicken farms in various regions of Thailand, including commercial and backyard farms. Gram-positive rods or cocci with catalase-negative characteristics from colonies showing a clear zone on MRS agar supplemented with 0.5% CaCO3 were identified using MALDI-TOF mass spectrometry. The LAB isolates were evaluated for acid (pH 2.5 and pH 4.5) and bile salt (0.3% and 0.7%) tolerance. Additionally, their cell surface properties, resistance to phenol, antimicrobial activity, hemolytic activity, and presence of antimicrobial resistance genes were determined. A total of 91 LAB isolates belonging to the Pediococcus, Ligilactobacillus, Limosilactobacillus, and Lactobacillus genera were obtained from chicken feces samples. Backyard farm feces exhibited a greater LAB diversity compared to commercial chickens. Five strains, including Ligilactobacillus salivarius BF12 and Pediococcus acidilactici BF9, BF14, BYF20, and BYF26, were selected based on their high tolerance to acid, bile salts, and phenol. L. salivarius BF12 and P. acidilactici BF14 demonstrated strong adhesion ability. The five LAB isolates exhibited significant cell-cell interactions (auto-aggregation) and co-aggregation with Salmonella. All five LAB isolates showed varying degrees of antimicrobial activity against Salmonella strains, with P. acidilactici BYF20 displaying the highest activity. None of the LAB isolates exhibited beta-hemolytic activity. Whole genome analysis showed that L. salivarius BF12 contained ermC, tetL, and tetM, whereas P. acidilactici strains BF9 and BF14 carried ermB, lnuA, and tetM. The selected LAB isolates exhibited basic probiotic characteristics, although some limitations were observed in terms of adhesion ability and the presence of antibiotic resistance genes, requiring further investigation into their genetic location. Future studies will focus on developing a probiotic prototype encapsulation for application in the chicken industry, followed by in vivo evaluations of probiotic efficacy.

Short Communication: Diversity of indigenous LAB from kefir grains cultured in goat milk based on phenotypic characteristics for probiotic candidates

Abstract. Wulansari PD, Rahayu N, Kusuma RJ, Sukarno AS. 2023. Short Communication: Diversity of indigenous LAB from kefir grains cultured in goat milk based on phenotypic characteristics for probiotic candidates. Biodiversitas 24: 6389-6395. Kefir grain is the starter of kefir products containing the symbiotic compound of lactic acid bacteria (LAB) and yeast. Microbial diversity in kefir grain is affected by multiple factors that include the origin of microbiota, upkeep, storage, and types of milk. Goat milk exhibits various superior properties in composition or characteristics. These have inspired the present study to obtain the local isolates from LAB derived from native Indonesian kefir grain produced and revitalized using goat milk. This study aimed to obtain local LAB isolates from kefir grain through phenotypic identification and characterization. The morphology of phenotypic identification consisted of macroscopic, microscopic, and biochemical identification. Based on macroscopic and microscopic observation, the isolates were milky white, circular, entire edge, smooth and shiny surface with convex elevation, coccus/basil shaped, Gram-positive, negative catalase, non-motile, non-spore, non-producing CO2, heterofermentative/homofermentative, able to ferment various carbohydrates, growing at 37 and 45°C, pH 4.4, and salinity level of 6.5%. A scientific approach enabled to obtaining of several LAB strains, namely nine isolates of Lactococcus and seven isolates of Lactobacillus. It takes genotypic identification to promote the identification process up to the species level.

Spectrum of vaginal lactic acid bacteria in indigenous and cross bred cows of India

Lactic acid bacteria (LAB) are beneficial microorganisms present in the bovine vagina. Documentation of LAB community in the vagina of indigenous and cross bred dairy cows of India is important to further establish its probiotic potential. The aim of this study was to isolate and identify the spectrum of LAB by phenotypic and genotypic methods. A total of 24 LAB were isolated from the vagina of 110 apparently healthy indigenous and cross bred cows. The LAB isolates belonged to the genus Lactobacillus, Bacillus, Enterococcus and Weisella and were further speciated based on their grouping with respective reference sequences available in the GenBank, on phylogenetic analysis. The species diversity of bovine vaginal LAB identified in this study was Lactobacillus agilis (17%), Lactobacillus mucosae (8%), Lactobacillus plantarum (21%), Lactobacillus fermentum (17%), Lactobacillus pentosus (4%), Weisella cibaria (8%), Bacillus coagulans (4%), Bacillus cereus (4%), Enterococcus faecium (13%) and Enterococcus asini (4%). The overall spectrum and relative abundance of the bovine vaginal LAB reported in this study provides critical information for the formulation of uterine probiotics for the prevention/treatment of bovine clinical endometritis.

The analysis of Lactobacillus spp. distribution in the vaginal microbiota of Polish women with abnormal Pap smear result.

A healthy vaginal microbiota is represented mainly by Lactobacillus spp. and plays a vital role in maintaining the functional balance in the vaginal environment. Scientists have drawn attention to possible correlations between the vaginal microbiome and gynecological neoplasms. Several recent studies have shown a potential link between the vaginal microbiome and the risk of developing cervical cancer from human papillomavirus (HPV) infection. This study aimed to compare the prevalence and abundance of various lactic acid bacteria species (LABs) in vaginal swabs from healthy controls and patients with abnormal Pap smear results. The study included 100 women (79 patients with abnormal cervical Pap smear results and 21 controls) from whom vaginal swabs were collected. Real-time quantitative PCR was used to determine seven lactic acid bacteria (LAB) species and their quantities. Most patients were colonized by two Lactobacillus species, primarily Lactobacillus gasseri (93%) and L. crispatus (83%). Patient age and place of residence were associated with the diversity of LAB in the vaginal microbiota. The abundance of L. delbrueckii in the vaginal microbiota increased, whereas the abundance of L. gasseri abundance decreased, with patient age. Lactobacillus acidophilus and Limosilactobacillus fermentum were significantly more often detected in patients living in rural versus urban areas. Statistical analysis did not show any significant differences in LAB between groups of patients with various changes on smear tests. The degree of dysplastic changes in the endothelium or the presence of a group of atypical cervical stratified epithelial cells was not associated with significant changes in the studied vaginal bacteria.

Lactiplantibacillus plantarum from Unexplored Tunisian Ecological Niches: Antimicrobial Potential, Probiotic and Food Applications.

The continued exploration of the diversity of lactic acid bacteria in little-studied ecological niches represents a fundamental activity to understand the diffusion and biotechnological significance of this heterogeneous class of prokaryotes. In this study, Lactiplantibacillus plantarum (Lpb. plantarum) strains were isolated from Tunisian vegetable sources, including fermented olive and fermented pepper, and from dead locust intestines, which were subsequently evaluated for their antimicrobial activity against foodborne pathogenic bacteria, including Escherichia coli O157:H7 CECT 4267 and Listeria monocytogenes CECT 4031, as well as against some fungi, including Penicillium expansum, Aspergilus niger, and Botrytis cinerea. In addition, their resistance to oro-gastro-intestinal transit, aggregation capabilities, biofilm production capacity, adhesion to human enterocyte-like cells, and cytotoxicity to colorectal adenocarcinoma cell line were determined. Further, adhesion to tomatoes and the biocontrol potential of this model food matrix were analyzed. It was found that all the strains were able to inhibit the indicator growth, mostly through organic acid production. Furthermore, these strains showed promising probiotic traits, including in vitro tolerance to oro-gastrointestinal conditions, and adhesion to abiotic surfaces and Caco-2 cells. Moreover, all tested Lpb. plantarum strains were able to adhere to tomatoes with similar rates (4.0-6.0 LogCFU/g tomato). The co-culture of LAB strains with pathogens on tomatoes showed that Lpb. plantarum could be a good candidate to control pathogen growth. Nonetheless, further studies are needed to guarantee their use as probiotic strains for biocontrol on food matrices.

Diversity of Decomposer Bacteria in Eco Enzyme Fermentation Process of Organic Materials Using Oxford Nanopore Technology (ONT) and its Effectiveness in Inhibiting E-coli in Fish Pond with Water Mineral Soil

Objective: This study aims to determine the characteristics of eco enzymes in the form of aroma, color, pH eco enzymes and identify the diversity of bacteria that play a role during the fermentation process. Method/design/approach: The research was carried out from August to December 2022, the first stage of making eco enzymes fermentation 3 months of organic waste three variants of Citrus sinensis Osb peel, Ananas comosus peel, and Citrullus lanatus peel, combined with 2 variants of vegetable residue of fern plants; Stenochlaena palutris and Diplazium esculentum. Eco enzyme yields were organoleptic tested and measured bacterial diversity with the Oxford Nanopore Technology (ONT) technique. Results and conclusion: Eco enzyme harvest organoleptic test results: pH 3.74, ethanol content 2.41%, color 1502 Pt.Co and the characteristic smell of fermentation. Bacterial diversity Test of bacterial diversity that plays a role during the eco enzyme fermentation process was carried out using the Oxford Nanopore Technology (ONT) technique, identified the diversity of lactic acid bacteria (BAL) at the taxon level, Phylum 7, Order 19, Familia 37, Genus 98 and species 269 lactic acid batteries (BAL). Eco enzyme 1 liter in 1000-1 liter of mineral groundwater fish pond can inhibit E-coli 36.1% of the original population. Research implications: This research contributes to the body of knowledge on eco enzymes, bacterial diversity in fermentation processes, and their potential applications in waste management and antibacterial activities. The implications of this study can pave the way for further research, innovations, and practical implementations in the field of eco-friendly technologies and sustainable waste management practices Originality/Value: The originality of this research lies in its focus on eco enzymes and bacterial diversity, while the value lies in its contribution to waste management practices, antibacterial applications, and advancements in environmentally friendly technology.

Augmented Reality-Based Lactic Acid Bacteria Diversity Flash Card Traditional Pakati'ng Rape’ Food

The impact of the Industrial Revolution 4.0 on education is to position education for modern learning. Modern learning must certainly involve learning media that can optimize the learning process. This study aims develop flash card media of lactic acid bacteria diversity of traditional food Pakati’ng Rape’ based on augmented reality. This research uses a research and development (R&D) method with the Alessi and Trollip development model and involves 9 validators to validate flash card learning media. This research instrument uses validation sheets consisting of language validation sheets, media validation sheets and material validation sheets with quantitative analysis techniques. For the practicality test, there is a student response questionnaire instrument. The results of this study are the development of flash card media diversity of lactic acid bacteria traditional food Pakati’ng Rape’ based augmented reality has been declared feasible with an average of 90.39% (is very practical). Based on the result of student responses, the average wa 79% (practical) in the small-scale test and 80% (practical) in the large-scale test. Flash card media diversity of lactic acid bacteria tradisional food Pakati’ng Rape’ based on agumented reality to be valid and practical so that it can be used in learning.

Isolation and some basic characteristics of lactic acid bacteria from beetroot (Beta vulgaris L.) —A preliminary study

The carbohydrate content of fruit and vegetable juices has made them a suitable environment for the growth of lactic acid bacteria. Various studies have shown that beetroot can be a good substrate for the production of probiotic drinks for consumers. Therefore, this study was performed to isolate and identify lactic acid bacteria from beetroot juice. Beetroot juice was prepared from two kilograms of washed beetroot with a cold press. Sterile samples of beetroot juice were first enriched in MRS broth and then cultured on MRS agar. Gram and catalase tests were used for the initial detection of lactic acid bacteria. Then, to identify the species of lactic acid bacteria, biochemical confirmation tests such as the melting of gelatin, and the growth of bacteria has been studied in the ideal condition that is 15-45° C, sugars fermentation, gas production from glucose, and growth in at different concentrations of salt were performed. The final verification of species was done using polymerase chain reaction-amplified 16S rRNA-specific DNA. All isolates formed creamy white round colonies on MRS agar medium, were gram-positive, were able to grow in anaerobic conditions, and were also rod-shaped and catalase-negative. Based on biochemical tests, four types of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus helveticus, Lactobacillus salivarius, and Lactobacillus acidophilus) were identified. The findings of this study indicated the presence and diversity of lactic acid bacteria in beet juice, which can be a potential platform for the production of probiotic beetroot juice as a non-dairy product.

Production of Soft Bloomy Rind Cheese with Lactic Acid Bacteria Isolated from Cameroon’s Cow Milk

The changing of the diversity of lactic acid bacteria (LAB) from one locality and another is one of the main reasons of the organoleptic and physicochemical differences encountered in the same class of cheese. The objective of this work was to evaluate the influence of LAB isolated from cow's milk produced locally in Cameroon on the organoleptic and physicochemical quality of soft cheese with bloomy rind. To this effect, 05 LAB (IS1, IS2, IS3, IS4 and IS5) were isolated to fresh milk and selected after macroscopic, microscopic and biochemical characterizations. After tests of acidification, fermentation type, compatibility between LAB and LAB concentration on milk coagulation, the combined IS1-IS4-IS5 and IS2-IS3-IS5 were retained to produce 02 soft cheeses with bloomy rind namely respectively FROCAM 145 and FROCAM 235. When used at concentrations of 3×107 CFU/mL, these combined LAB coagulate fresh renneted milk after 3 hours at 26°C. During the production of FROCAM 145, the combined IS1-IS4-IS5 resulted in a firm, moist curd and a pH reduction of 14 and 15% respectively after the milk maturation and ripening of FROCAM 145. This cheese recorded 100% mould recovery, with protein, lipid and calcium content of 6.7, 62.2 and 0.1% respectively. On the other hand, during the production of FROCAM 235, the combined IS2-IS3-IS5 resulted in a dry and crumbly curd. The pH recorded with this combined LAB after maturation of the milk and ripening of FROCAM 235 is 12 and 17% respectively. The FROCAM 235 recorded a low mould recovery estimated at 20% and a protein, lipid and calcium content of 7.8, 65.1 and 0.3% respectively. From a microbiological point of view, FROCAM 145 and FROCAM 235 did not record any contamination by Listeria monocytogenes, Salmonella and Staphylococci. The sensory analysis shows that FROCAM 145 was more appreciated than FROCAM 235 with scores of 0.74 and 0.24 respectively. In view of these results, the IS1-IS4-IS5 combinations isolated from Cameroonian milks present a certain technological interest in the transformation of milk into cheese.

Influence of Isolation Temperature on Isolating Diverse Lactic Acid Bacteria from Kimchi and Cultural Characteristics of Psychrotrophs.

Kimchi is a traditional Korean fermented vegetable that is stored and fermented at low temperatures. However, kimchi lactic acid bacteria (LAB) are typically isolated under mesophilic conditions, which may be inappropriate for isolating the diverse LAB. Therefore, this study investigated the suitable conditions for isolating various LAB from kimchi. Here, LAB were isolated from four kimchi samples using MRS, PES, and LBS media and varying isolation temperatures (30, 20, 10, and 5°C). Then, MRS was selected as the suitable medium for LAB isolation. A comparison of culture-dependent and culture-independent approaches indicated that 5°C was not a suitable isolation temperature. Thus, the number and diversity of LAB were determined at 30, 20, and 10°C using 12 additional kimchi samples to elucidate the effect of isolation temperature. With the exception of two samples, most samples did not substantially differ in LAB number. However, Leuconostoc gelidum, Leuconostoc gasicomitatum, Leuconostoc inhae, Dellaglioa algida, Companilactobacillus kimchiensis, Leuconostoc miyukkimchii, Leuconostoc holzapfelii, and Leuconostoc carnosum were isolated only at 10 and 20°C. The growth curves of these isolates, except Leu. holzapfelii and Leu. carnosum, showed poor growth at 30°C. This confirmed their psychrotrophic characteristics. In Weissella koreensis, which was isolated at all isolation temperatures, there was a difference in the fatty acid composition of membranes between strains that could grow well at 30°C and those that could not. These findings can contribute to the isolation of more diverse psychrotrophic strains that were not well isolated under mesophilic temperatures.

Biodiversity of Lactic Acid Bacteria in Traditional Fermented Foods in Yunnan Province, China, and Comparative Genomics of Lactobacillus plantarum

The diversity of lactic acid bacteria (LAB) in fermented foods in Yunnan currently lacks large-scale and systematic research. A total of 638 fermented foods were collected from 84 regions in Yunnan for diversity analyses. The results show that the dominant strains in various types of fermented foods were different. Additionally, the majority of the LAB were better adapted to regions with a temperature of 15–20 °C and a humidity of 64–74%. Lactobacillus plantarum (L. plantarum) was the most abundant of all the strains and was widely distributed in the 84 regions. Genetically, the guanine plus cytosine (GC) content of L. plantarum ranged from 35.60% to 47.90%, with genome sizes from 2.54 Mb to 5.76 Mb. A phylogenetic analysis revealed that the habitat source and geographic origin had little influence on the homologous genes of L. plantarum. The genetic diversity of L. plantarum was mostly represented by functional genes and carbohydrate utilization. This research provides valuable insights into the microbiota of different types of fermented foods in Yunnan. Meanwhile, a genetic diversity analysis of L. plantarum may help us to understand the evolutionary history of this species.

Bacterial diversity and its correlation with sensory quality of two types of zha-chili from Shennongjia region, China

In the Shennongjia region of China, two types of zha-chili with distinct flavors exist: the first type (P zha-chili) uses a significant amount of chili pepper but no potato, while the other (PP zha-chili) contains a smaller amount of chili pepper but a proportion of potato. In order to investigate the bacterial diversity and sensory properties of these two types of zha-chili, this study employed a combination of amplicon sequencing, culture-based methods, and sensory technology. The results of the study showed statistically significant differences (P < 0.05) in bacterial diversity and communities between the two types of zha-chili. In particular, four dominant lactic acid bacteria (LAB) genera - Lactiplantibacillus, Lactococcus, Leuconostoc, and Weissella - were significantly enriched in PP zha-chili. The findings suggest that the proportions of chili pepper and potato can influence the bacterial diversity and content of LAB, with a higher proportion of chili pepper potentially inhibiting the growth of harmful species within the Enterobacteriaceae family. The study also used culture-based methods to identify the most dominant bacteria in the zha-chili samples as Lactiplantibacillus plantarum group, Companilactobacillus alimentarius, and Lacticaseibacillus paracasei. Correlation analysis indicated that LAB likely plays a significant role in shaping the aroma profile of zha-chili, with Levilactobacillus, Leuconostoc, Lactiplantibacillus, and Lactococcus showing correlation with E-nose sensory indices. However, these LAB were not significantly correlated with the taste properties of zha-chili. The study provides new insights into the influence of chili pepper and potato on the microbial diversity and flavor properties of zha-chili, and also presents potential LAB isolates for future research on zha-chili.

Persistence of maternal milk derived Lactobacillus plantarum in the infant feces and its antagonistic activity against Escherichia coli O157:H7.

The diversity of lactic acid bacteria (LAB) in maternal milk and feces from Thai mother-infants pairs were revealed through nested PCR-DGGE. LAB species residing in maternal milk drawn from each individual demonstrated high uniqueness, yet shared similarity to her infant. Multiple strains of L. plantarum, L. fermentum, L. rhamnosus, L. mucosae, L. casei were continuously detected, suggesting direct transfer from a mother to her infant via breastfeeding. L. plantarum, the most commonly found species with many strain variants, remained persistent in infant's feces up to six months postpartum. Such success could be achieved through its ability to utilize fructooligosaccharides (FOS)/inulin together with antibacterial activity and competitive adhesion. With FOS/inulin, the prebiotic utilizing L. plantarum (M117 and M118) isolated from maternal milk effectively inhibited E. coli O157:H7 under highly microflora competitive and glucose-limited environments of colon model. The results introduce the potential trend for development of effective anti-diarrheal synbiotic infant formulae.