Techno-functional characterization of indigenous Lactobacillus isolates from the traditional fermented foods of Meghalaya, India

Evaluation of the techno-functional properties of lactobacilli strains originated from Bos indicus and Bubalus bubalis calves for probiotic potential

The current study was undertaken to isolate, characterize, and cluster lactobacilli strains of indigenous cattle (Bos indicus) and buffalo (Bubalus bubalis) calf origin to develop a species-specific multistrain potential probiotic adjunct. Bacterial strains were isolated from the feces of Bos indicus and Bubalus bubalis calves of different breeds, i.e., Sahiwal (SC), Tharparker (TP), and Gir (GC) cattle and Murrah buffalo (MB). The fecal samples were aseptically taken from five healthy calves (5-10 days old) of each breed (a total of 20 animals). Accordingly, 105 bacteria were isolated, 52 of which were catalase negative, Gram-positive, and vancomycin resistant. These isolates were presumed to be Lactobacillus species, and genus-specific PCR was used to confirm their identification. Among the 52 isolates, 22 strains demonstrated greater acid tolerance, while 29 isolates showed superior bile tolerance, with survivability greater than 90%. Fifteen isolates capable of tolerating both acid and bile were further selected, and their identities were confirmed via 16S rRNA sequencing. Cluster analysis of the phylogenetic tree revealed three different species: Ligilactobacillus salivarius (8), Ligilactobacillus agilis (1), and Limosilactobacillus reuteri (6). All lactobacilli strains showed coaggregation with Escherichia coli ATCC25922 and Salmonella arizonae ATCC13314. All the isolates were found non-hemolytic and non-mucinolytic. Principal component analysis (PCA) revealed that L. reuteri GC09, L. salivarius GC12, L. agilis MB08, L. salivarius MB14, L. reuteri SC01, and L. reuteri MB11 possessed the most desirable attributes of probiotics. Based on these findings, these strains could be used to develop multi-strain probiotic adjunct for calves.

Safety Assessment and Evaluation of Probiotic Potential of Lactobacillus bulgaricus IDCC 3601 for Human Use

Lactic acid bacteria (LAB) are probiotic microorganisms widely used for their health benefits in the food industry. However, recent concerns regarding their safety have highlighted the need for comprehensive safety assessments. In this study, we aimed to evaluate the safety of L. bulgaricus IDCC 3601, isolated from homemade plain yogurt, via genomic, phenotypic, and toxicity-based analyses. L. bulgaricus IDCC 3601 possessed a single circular chromosome of 1,865,001 bp, with a GC content of 49.72%, and 1910 predicted coding sequences. No virulence or antibiotic resistance genes were detected. Although L. bulgaricus IDCC 3601 exhibited antibiotic resistance to gentamicin and kanamycin, this resistance is an intrinsic feature of this species. L. bulgaricus IDCC 3601 did not produce biogenic amines and did not exhibit hemolytic activity. Phenotypic analysis of enzyme activity and carbohydrate fermentation profiles revealed the metabolic features of L. bulgaricus IDCC 3601. Moreover, no deaths or abnormalities were observed in single-dose oral toxicity tests, suggesting that L. bulgaricus IDCC 3601 has no adverse effect on human health. Finally, L. bulgaricus IDCC 3601 inhibited the growth of potential carbapenem-resistant Enterobacteriaceae. Therefore, our results suggest that L. bulgaricus IDCC 3601 is a safe probiotic strain for human consumption.

Targeted Screening of Fiber Degrading Bacteria with Probiotic Function in Herbivore Feces

Cellulolytic bacteria with probiotic functions play a crucial role in promoting the intestinal health in herbivores. In this study, we aimed to correlate the 16S rRNA gene amplicon sequencing and fiber-degrading enzyme activity data from six different herbivore feces samples. By utilizing the separation and screening steps of probiotics, we targeted and screened high-efficiency fiber-degrading bacteria with probiotic functions. The animals included Maiwa Yak (MY), Holstein cow (CC), Tibetan sheep (TS), Southern Sichuan black goat (SG), Sichuan white rex rabbit (CR), and New Zealand white rabbit (ZR). The results showed that the enzymes associated with fiber degradation were higher in goat and sheep feces compared to cattle and rabbit's feces. Correlation analysis revealed that Bacillus and Fibrobacter were positively correlated with five types of fiber-degrading related enzymes. Notably, the relative abundance of Bacillus in the feces of Tibetan sheep was significantly higher than that of other five herbivores. A strain TS5 with good cellulose decomposition ability from the feces of Tibetan sheep by Congored staining, filter paper decomposition test, and enzyme activity determination was isolated. The strain was identified as Bacillus velezensis by biological characteristics, biochemical analysis, and 16S rRNA gene sequencing. To test the probiotic properties of Bacillus velezensis TS5, we evaluated its tolerance to acid and bile salt, production of digestive enzymes, antioxidants, antibacterial activity, and adhesion ability. The results showed that the strain had good tolerance to pH 2.0 and 0.3% bile salts, as well as good potential to produce cellulase, protease, amylase, and lipase. This strain also had good antioxidant capacity and the ability to antagonistic Staphylococcus aureus BJ216, Salmonella SC06, Enterotoxigenic Escherichia coli CVCC196, and Escherichia coli ATCC25922. More importantly, the strain had good self-aggregation and Caco-2 cell adhesion rate. In addition, we tested the safety of Bacillus velezensis TS5 by hemolysis test, antimicrobial susceptibility test, and acute toxicity test in mice. The results showed that the strain had no hemolytic phenotype, did not develop resistance to 19 commonly used antibiotics, had no cytotoxicity to Caco-2, and did not have acute toxic harm to mice. In summary, this study targeted isolated and screened a strain of Bacillus velezensis TS5 with high fiber-degrading ability and probiotic potency. This strain can be used as a potential probiotic for feeding microbial preparations for ruminants.

Safety aspects, probiotic potentials of yeast and lactobacillus isolated from fermented foods in North-Eastern India, and its anti-inflammatory activity

Lactobacillus and yeast obtained from fermented foods in North-East India were tested for safety and probiotic properties. All the lactobacilli and yeast tested negative for the catalase, indole, urease, phenylalanine, hemolysis, gelatin hydrolysis, and biogenic amine production tests, indicating that they are safe to use as probiotics in food supplements. Lactiplantibacillus plantarum KGL3A (accession no. MG722814) was capable of resisting the replicated gastric fluid (pH 2) till 2 h of exposure, whereas both KGL3A and Lacticaseibacillus rhamnosus K4E (accession no. KX950834.1) strains were able to resist pH 3 till 2 h of exposure with a reduction in overall viable cell count from 7.48 log CFU/mL to 1.09 log CFU/mL and 7.77 log CFU/mL to 0.83 log CFU/mL, respectively. In vitro gastric juice simulation conditions were tolerated by the yeast Saccharomyces cerevisiae WBS2A. The cell surface hydrophobicity (CSH) towards hydrocarbons (n-hexadecane) was seen highest in L. plantarum KGL3A (77.16± 0.84%) and Limosilactobacillus fermentum KGL4 accession no. MF951099 (72.60 ± 2.33%). The percentage auto-aggregation ranged from 8.70 to 25.53 after 2 h, which significantly increased to 10.50 to 26.94 during the fifth hour for cultures. Also, a higher percentage of co-aggregation was found for the culture L. rhamnosus K4E with S. typhi (34.18 ± 0.03%), E. coli (32.97 ± 0.02 %) and S. aureus (26.33 ± 0.06 %) and for the yeast S. cerevisiae WBS2A, a higher percentage of co-aggregation was found with Listeria monocytogenes (25.77 ± 0.22%). The antioxidant activity and proteolytic activity were found to be higher for Lactobacillus helveticus K14 and L. rhamnosus K4E. The proportion of decreased cholesterol was noticeably higher in KGL4 (29.65 ± 4.30%). β glucosidase activity was significantly higher in the L. fermentum KGL4 strain (0.359 ± 0.002), and α galactosidase activity was significantly higher in the L. rhamnosus K4E strain (0.415 ± 0.016). MTT assays suggested that KGL4 and WBS2A at a lower dose did not exhibit cytotoxicity.

Techno-functional characterization of fecal lactobacilli isolates of Bos indicus calves for probiotic properties

In this study, 105 bacterial colonies were isolated from the feces of newborn healthy Bos indicus calves and 37 isolates were confirmed using morphological, biochemical tests, and genus-specific PCR as lactobacilli. 11 isolates were then short-listed for in vitro probiotic testing based on their ability to dwell under acid and bile stress. Species-level identification using 16S rRNA gene sequencing revealed that they were Ligilactobacillus salivarius. These isolates flourished in 0.4% phenol, depicting resistance in adverse conditions encountered in the gastrointestinal tract. The results of cell surface hydrophobicity were found to be 74.50% for RBL12 and 62.62% for RBL09 in hexadecane and xylene, respectively, and that of auto-aggregation was highest in RBL26 (58.92%). These isolates also produced digestive enzymes like amylase, protease, and β-galactosidase. Further assays reiterated their antimicrobial and coaggregation potential against diarrhea-causing pathogens like Escherichia coli ATCC-25922 and Salmonella arizonae ATCC-13314. Biosafety assessment revealed that none of the tested isolates were hemolytic and mucinolytic in nature. Furthermore, the antioxidant potential of the isolates was also confirmed using 1,1‑diphenyl‑2‑picrylhydrazyl (DPPH) and ferric ion-reducing antioxidant power (FRAP) assay. Along with efficient utilization of inulin, isolates showed promising adhesion ability to the HT-29 cell line. The current findings hence conclude that these Lactobacillus isolates can be exploited as animal probiotics for potential application in young calves to foster gut health and immunity.

In vitro safety assessment of electrohydrodynamically encapsulated Lactiplantibacillus plantarum CRD7 and Lacticaseibacillus rhamnosus CRD11 for probiotics use

The current study aimed to validate the safety of electrohydrodynamically encapsulated Lactiplantibacillus plantarum CRD7 and Lacticaseibacillus rhamnosus CRD11 in accordance with guidelines of FAO/WHO and ICMR/DBT. In vitro assays such as mucin degradation, hemolysis of blood cells, antimicrobial susceptibility pattern, possession of virulence factors, biogenic amine, and ammonia production were assessed. In results, the cross-streak and co-culture techniques revealed that CRD7 and CRD11 were compatible in vitro. Upon visual inspection through scanning electron and fluorescence microscopy, the integrity of bacterial cell membrane was confirmed even after the encapsulation process. CRD7 and CRD11 were non-hemolytic and showed negative responses to gelatinase, urease, and DNase activities. Non-mucinolytic activity of CRD7 and CRD11 was verified by measuring cell growth rate (p < 0.05) in different modified media followed by SDS-PAGE. High-performance liquid chromatography analysis revealed that both the strains did not produce biogenic amines (putrescine, cadaverine, histamine, and tyramine). Neither of the Lactobacillus strains produced ammonia after growing in BHI broth for 5 days at 37 °C. L-lactate production was highest (p < 0.05) in CRD11 (8.83 g/L), followed by CRD7 (8.16 g/L), whereas the lowest (p < 0.05) D-lactate was registered for encapsulated CRD11 (0.33 g/L) and CRD7 (0.49 g/L). The antibiogram profile determined through minimum inhibitory concentration showed that CRD7 and CRD11 were sensitive to key antibiotics suggested by EFSA except for gentamycin and kanamycin. PCR data on virulence genes demonstrated that both strains were safe for probiotic use. Moreover, CRD7 and CRD11 strains caused insignificant (p > 0.05) changes in the cell viability of Caco-2 cells as estimated by MTT (98.94-99.50%) and NR uptake (95.42-97.03%) assays and showed sensitivity to human serum. According to the results of these evaluated attributes, it is concluded that L. plantarum CRD7 and L. rhamnosus CRD11 are safe, non-toxic to human epithelial cells, and thus may be potentially suitable for various food/feed applications.

Functional Characterization of Lactobacillus plantarum Isolated from Cow Milk and the Development of Fermented Coconut and Carrot Juice Mixed Beverage

Screening probiotics are crucial for assessing their safety, security, and further production of functional foods for human health. The present study aimed to isolate and identify bacteria from raw cow's milk samples that exhibit health benefits upon consumption. We characterized the probiotic properties of Lactobacillus plantarum (also called Lactiplantibacillus plantarum) strains CMGC2 and CMJC7 isolated from cow milk by in vitro study. The strains exhibited tolerance to simulated gastric conditions and were further identified by 16S rRNA sequencing as Lactobacillus plantarum (L. plantarum) CMGC2 and CMJC7. Both isolates were evaluated in vitro for their probiotic attributes, viz. hydrophobicity, autoaggregation, co-aggregation, lysozyme tolerance, antibacterial activity, antibiotic susceptibility, hemolytic activity, and phenol tolerance. The isolates CMGC2 and CMJC7 showed excellent probiotic attributes; hence, both strains were selected to produce coconut and carrot juice mixed beverages (CCMB). The CCMB was evaluated for the pH, acid-production rate, and total viable bacterial counts. The results showed that the CCMB was an excellent medium for the growth of CMGC2 and CMJC7 as it supported adequate growth of organisms (8.93 CFU/mL and 8.68 CFU/mL, respectively) even after 48 h of incubation. In conclusion, CMGC2 and CMJC7 can be used to develop different beverages possessing nutritive and probiotic values, and these beverages can be used for producing unique products.

Genomic and probiotic attributes of Lactobacillus strains from rice-based fermented foods of North Eastern India

The probiotic attributes and genomic profiles of amylase-producing Lactobacillus strains from rice-based fermented foods of Meghalaya in the North-Eastern India were evaluated in the study. A preliminary screening of 17 lactic acid bacteria strains was performed based on their starch hydrolysis and glucoamylase activities. Out of 17 strains, 5 strains (L. fermentum KGL4, L. rhamnosus RNS4, L. fermentum WTS4, L. fermentum KGL2, and L. rhamnosus KGL3A) were selected for further characterization of different probiotic attributes. Whole-genome sequencing of two of the best strains was carried out using a shotgun sequencing platform based on their rich probiotic attributes. The EPS production was in the range of 2.89-3.92 mg/mL. KGL2 (41.5%) and KGL3A (41%) showed the highest antioxidant activity. The highest antibiotic susceptibility was exhibited by all the five Lactobacillus strains against ampicillin, ranging from 24.66 to 27.33 mm. The lactobacilli isolates used in the study could survive the simulated gastric/intestinal juices. Genomic characterization of KGL4 and KGL3A illustrated their possible adherence to the intestinal wall, specialized metabolic patterns, and possible role in boosting host immunity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05633-8.

Genotyping of Probiotic Lactobacilli in Nigerian Fermented Condiments for Improved Food Safety

BACKGROUND: Plant-based naturally fermented condiments usually result in poor quality products with various bacteria and fungi contaminants. Previous reports suggested the use of starter cultures from previously fermented condiments in fermentation processes to ensure health-promoting benefits, improved quality, shelf life, and organoleptic properties for the achievement of healthy nutrition, safe, and quality food. AIM: This study aimed to genotype potential lactobacilli from locally fermented condiments for improved food safety. METHODS: The lactobacilli colonies isolated from fermented condiments purchased from food markets in Southwest Nigeria were profiled for probiotic activities, hemolytic activities, antibiotics susceptibility, and inhibitory activities against food pathogens. Interesting probiotic lactobacilli were identified using 16S rRNA gene sequencing and evaluated for phylogenetic relatedness with other globally reported probiotic lactobacilli. RESULTS: Lactobacillus species which expressed significant probiotics, γ-hemolysis, anti-spoilage, and anti-listerial activities (P < 0.05) with tolerable safety profiles were identified as Lactiplantibacillus plajomi YD001 (MW280136), Lactiplantibacillus plantarum YD002 (MW280139), L. plantarum YD003 (MW280137), and Lacticaseibacillus paracasei YD004 (MW280138) possessed 50.75, 50.61, 50.75, and 52.54 mol% DNA G+C contents, respectively. The species clustered into different phylogroups with high clonal relatedness with other potential lactobacilli meta-data (≥96.80%) obtained from the public repository. CONCLUSION: Obtained genotyped Lactobacillus species are potential starter cultures for improved fermentation processes, control of food pathogens, and spoilage organisms.

Evaluation of the Probiotic Potential of Lactobacillus delbrueckii ssp. indicus WDS-7 Isolated from Chinese Traditional Fermented Buffalo Milk In Vitro

The present study aimed to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from Chinese traditional fermented buffalo milk. Out of 22 isolates, 11 were putatively identified as LAB preliminarily. A total of six LAB strains displayed strong adhesion to HT-29 cells and all these strains showed preferable tolerance to artificially simulated gastrointestinal juices. WDS-4, WDS-7, and WDS-18 exhibited excellent antioxidant capacities, including DPPH radical, ABTS⁺ radical, and superoxide anion scavenging activities. Compared with the other two LAB strains, WDS-7 had a stronger inhibition effect on four pathogens. Based on the 16S rRNA gene sequencing and phylogenetic analysis, WDS-7 was identified as Lactobacillus delbrueckii ssp. indicus and selected to assess the potential and safety of probiotics further. The results revealed that WDS-7 strain had a strong capacity for acid production and good thermal stability. WDS-7 strain also possessed bile salt hydrolase (BSH) activity. Compared to LGG, WDS-7 was a greater biofilm producer on the plastic surface and exhibited a better EPS production ability (1.94 mg/ml as a glucose equivalent). WDS-7 was proved to be sensitive in the majority of tested antibiotics and absence of hemolytic activity. Moreover, no production of biogenic amines and β-glucuronidase was observed in WDS-7. The findings of this work indicated that L. delbrueckii ssp. indicus WDS-7 fulfilled the probiotic criteria in vitro and could be exploited for further evaluation in vivo.

Optimization of an economical medium composition for the coculture of Clostridium butyricum and Bacillus coagulans

Clostridium butyricum is a spore-forming probiotic which can promote the enhancement of beneficial bacteria and maintain intestinal microecological balance. However, it is difficult to improve the production level of C. butyricum by conventional fermentation process. In this study, a co-fermentation process of C. butyricum DL-1 and Bacillus coagulans ZC2-1 was established to improve the viable counts and spore yield of C. butyricum, and the formula of coculture medium was optimized by flask fermentation. The results showed that the optimum medium composition is 10 g/L bran, 15 g/L corn steep powder, 15 g/L peptone, 1 g/L K₂HPO₄ and 0.5 g/L MnSO₄.Cultured stationarily in the optimal medium for 36 h, the number of viable bacteria of C. butyricum DL-1 reached 1.5 × 10⁸ cfu/mL, Which was 375 times higher than that incubated in the initial medium. The sporulation rate reach 92.6%. The results revealed an economical and effective medium composition for the coculture of C. butyricum and B. coagulans, which achieved a 64.6% cost reduction. The co-fermentation process established in this study provides a new fermentation mode for the industrial production of other absolute anerobic bacteria.

"Ethno-microbiology" of ethnic Indian fermented foods and alcoholic beverages

The concept of "ethno-microbiology" is to understand the indigenous knowledge of the Indian people for production of culturally and organoleptically acceptable fermented foods by natural fermentation. About 1000 types of common, uncommon, rare, exotic and artisan fermented foods and beverages are prepared and consumed in different geographical regions by multi-ethnic communities in India. Indian fermented foods are mostly acidic and some are alkaline, along with various types of alcoholic beverages. A colossal diversity of microorganisms comprising bacteria mostly belongs to phylum Firmicutes, filamentous moulds and enzyme- and alcohol-producing yeasts under phyla Ascomycota and Mucoromycota, and few bacteriophages and archaea have been reported from Indian fermented foods. Some microorganisms associated with fermented foods have functionalities and health promoting benefits. "Ethno-microbiology" of ethnic Indian people has exhibited the proper utilisation of substrates either singly or in combination such as fermented cereal-legume mixture (idli, dosa and dhokla) in South and West India, sticky fermented soybean food (kinema and related foods), fermented perishable leafy vegetable (gundruk and related foods), fermented bamboo shoots (soibum and related foods) and fermented fish (ngari and others) in North East India, and fermented meat and sausage-like products in the Indian Himalayas, fermented coconut beverage (toddy) in coastal regions, and various types of naturally fermented milk products (dahi and related products) in different regions of India. This review has also highlighted the "ethno-microbiology" knowledge of the people involving the consortia of essential microorganisms in traditionally prepared amylolytic starters for production of cereal-based alcoholic beverages. The novelty of this review is the interpretation of ethno-microbiological knowledge innovated by ethnic Indian people on the use of beneficial microorganisms for food fermentation to obtain the desired fermented food products for consumption.

Diversity of beneficial microorganisms and their functionalities in community-specific ethnic fermented foods of the Eastern Himalayas

The Eastern Himalayan regions of India, Nepal and Bhutan have more than 200 varieties of unsurpassed ethnic fermented foods and alcoholic beverages, which are lesser known outside the world. However, these ethnic foods are region- and community-specific, unique and some are exotic and rare, which include fermented vegetables, bamboo shoots, soybeans, cereals, milk (cow and yak), meats, fishes, and cereal-based alcoholic beverages and drinks. Ethnic communities living in the Eastern Himalayas have invented the indigenous knowledge of utilization of unseen microorganisms present in and around the environment for preservation and fermentation of perishable plant or animal substrates to obtain organoleptically desirable and culturally acceptable ethnic fermented food and alcoholic beverages. Some ethnic fermented products and traditionally prepared dry starters for production of alcoholic beverages of North Eastern states of India and Nepal were scientifically studied and reported till date, and however, limited publications are available on microbiological and nutritional aspects of ethnic fermented foods of Bhutan except on few products. Most of the beneficial microorganisms isolated from some ethnic fermented foods of the EH are listed in microbial food cultures (MFC) safe inventory. This study is aimed to review the updates on the beneficial importance of abundant microbiota and health-promoting benefits and functionalities of some ethnic fermented foods of the Eastern Himalayan regions of North East India, Nepal and Bhutan.

Impact of Lactobacillus cultures on production of B-vitamins, organic acids and biotransformation of soy isoflavones

In the study, four potent Lactobacillus cultures of L. rhamnosus K4E, L. plantarum RD7, L. fermentum K7, and L. fermentum K16 were considered for the production of B-vitamins, organic acids and biotransformation of soy isoflavones. L. plantarum RD7 showed the highest B2 production (0.84 μg mL−1) after 36 h, while L. fermentum K16 exhibited maximum B12 production (0.084 μg mL−1) after 12 h. L. rhamnosus K4E produced 0.24 μg mL−1 of folate after 12 h. Highest production of lactate (16.43 μg mL−1) and acetate (5.86 μg mL−1) was reported by L. rhamnosus K4E. L. plantarum RD7 showed maximum butyrate (0.253 μg mL−1) production compared to the other cultures. The highest bioconversion of soy aglycones was reported by L. rhamnosus K4E with 55.43% for daidzein and 72.30% for genistein, during soymilk fermentation. These potent cultures have a potential to be used as functional starter cultures for the production of functional fermented soy foods.

Lactobacillus commensals autochthonous to human milk have the hallmarks of potent probiotics

Maternal milk is an important source of essential nutrients for the optimal growth of infants. Breastfeeding provides a continuous supply of beneficial bacteria to colonize the infant gastrointestinal tract (GIT) and offers health benefits for disease prevention and immunity. The purpose of this study was to isolate novel probiotic strains from the breast milk of native Pakistani mothers and to evaluate their probiotic potential. We isolated 21 strains of bacteria from the colostrum and mature milk of 20 healthy mothers, who had vaginal deliveries and were not taking antibiotics. After phenotypic and genotypic characterization, these isolates were tested for survival in the GIT using in vitro acid and bile tests. Nine strains showing good acid tolerance were assessed for their growth rate, bile resistance and ability to hydrolyze bile salts. Out of the four Lactobacillus isolates adjudged to be most promising as probiotics, three were Lactobacillus fermentum strains and one was a strain of Lactobacillus oris. This study demonstrates that human milk is a viable source of commensal bacteria beneficial to both adults and babies.