Phytase-Producing Potential and Other Functional Attributes of Lactic Acid Bacteria Isolates for Prospective Probiotic Applications

DIVERISTY and enzymatic potential of indigenous bacteria from unexplored contaminted soils in Faisalabad

Bacteria residing in contaminated waste soil degrade and utilize organic and inorganic material as a source of nutrients as well as reduce environmental contamination through their enzymatic machinery. This enzymatic potential of indigenous bacteria can be exploited at industrial level through detailed screening, characterization, optimization and purification. In present study, diversity and enzymatic potential of indigenous bacteria was investigated through qualitative and quantitative screening methods from unexplored contaminated soil waste sites in Faisalabad. Shannon diversity (H') index revealed that twenty-eight soil samples from four contaminated sites were highly diverse of amylase, protease and lipase producing bacteria. Maximum protease producing bacteria were detected in fruit waste (1.929 × 10⁷), whereas amylase and lipase producing bacteria were found in industrial (1.475 × 10⁷) and (5.38 × 10⁶), in household waste soil samples. Most of the indigenous bacterial isolates showed potential for multiple enzymes. An isolate OC5 exhibited capability for amylase production and optimization at a wider range of cultural conditions; pH (6-8), temperature (25 °C, 37 °C, 45 °C), incubation time (24-72 h), and NaCl concentrations 0.5-13%, using (1%) starch and lactose as substrates. An isolate OC5 was identified by molecular identification and phylogenetic analysis showed 99% sequence similarity with Bacillus spp. ANOVA was used to analyzed all data statistically. This study enhances the importance of initial screening and reporting of industrially potent indigenous bacteria from unexplored contaminated waste soils. In future, indigenous bacteria in contaminated wastes may be good candidates to solve various environmental pollution problems.

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.

Pulse Probiotic Superfood as Iron Status Improvement Agent in Active Women-A Review

Active women or women of reproductive age (15–49 years old) have a high risk of suffering from anaemia. Anaemia is not solely caused by iron deficiency, however, the approaches to improve iron status in both cases are greatly related. Improving the iron status of active women can be done by dietary intervention with functional food. This review aims to provide insights about the functional food role to increase iron absorption in active women and the potency of pulse probiotic superfood development in dry matrices. Results showed that the beneficial effect of iron status is significantly improved by the synergic work between probiotic and prebiotic. Furthermore, chickpeas and lentils are good sources of prebiotic and the consumption of pulses are related with 21st century people’s intention to eat healthy food. There are wide possibilities to develop functional food products incorporated with probiotics to improve iron status in active woman.

Enterococcus faecium Modulates the Gut Microbiota of Broilers and Enhances Phosphorus Absorption and Utilization

Modern broiler chickens have ongoing bone health problems. Phosphorus (P) plays an important role in bone development and increased understanding of P metabolism should improve the skeletal health of broilers. Enterococcus faecium has been widely used as a probiotic in broiler production and is shown to improve skeletal health of rats, but its effect on the bones of broilers remains unclear. This study investigated the effect of E. faecium on P absorption and utilization in broilers and the associated changes in the gut microbiota using 16S rDNA sequencing. Dietary supplementation with E. faecium improved P absorption through upregulation of the expression of intestinal NaP-IIb mRNA and increased the concentration of serum alkaline phosphatase. These actions increased P retention and bone mineralization in E. faecium-treated broilers. The positive effects of E. faecium on P metabolism were associated with changes in the populations of the intestinal microbiota. There was increased relative abundance of the following genera, Alistipes, Eubacterium, Rikenella and Ruminococcaceae and a decrease in the relative abundance of Faecalibacterium and Escherichia-Shigella. Dietary supplementation with E. faecium changed gut microbiota populations of broilers, increased the relative abundance of SCFA (short-chain fatty acid)-producing bacteria, improved intestinal P absorption and bone forming metabolic activities, and decreased P excretion. E. faecium facilitates increased utilisation of P in broilers.

Multifarious cholesterol lowering potential of lactic acid bacteria equipped with desired probiotic functional attributes

Lactic acid bacteria (LAB) isolates possessed functional probiotic attributes, such as high hydrophobicity and autoaggregation ability, coaggregation capability with bacterial pathogens, antimicrobial activity, antioxidant potential, and hypocholesterolemic effects. Selected potential probiotic LAB, i.e. Lactobacillus paracasei M3, L. casei M5, L. paracasei M7, and few others were studied for their ability to lower cholesterol using a number of methods viz. cholesterol assimilation, bile salt deconjugation, cholesterol co-precipitation, cholesterol adhesion to probiotic cell wall, and miceller sequestration of cholesterol. L. casei M5 showed maximum bile salt hydrolase (BSH) activity, and released 57.63 nmol of glycine/min, and was closely followed by LAB isolate M9 which generated 52.12 nmol of glycine/min. Sodium glycocholate was deconjugated by L. casei M5 to produce 27.77 μmol/mL of cholic acid, while other isolates produced 20-26 μmol/mL of cholic acid. Cholesterol was assimilated significantly by isolate M6 (82.15%) and L. casei M5 (76.51%). L. casei M5 showed higher cholesterol co-precipitation ability (50.16 μg/mL) as compared to other LAB isolates (33-44 μg/mL). Miceller cholesterol concentration was reduced maximally by LAB isolate M8 (87.5%), followed by isolates M5 (84.75%), M9 (84%), M10 (80%), and M37 (79%). Higher cell wall adhesion of cholesterol was realized by L. casei M5 (42.48 μg/mL) than other LAB isolates (30-40 μg/mL). Selected LAB probiotics demonstrated short chain fatty acid (acetate, propionate, and butyrate) producing ability, yet another way of probiotics-mediated cholesterol lowering.

Safety Evaluation and Colonisation Abilities of Four Lactic Acid Bacteria as Future Probiotics

The study evaluated the safety and colonisation properties of four lactic acid bacteria (LAB), by determining their cell hydrophobicity and aggregation abilities. In addition, the presence of virulence and resistance genes was assayed in these probiotic candidates. Lactobacillus reuteri ZJ625, Lactobacillus reuteri VB4, Lactobacillus salivarius ZJ614 and Streptococcus salivarius NBRC13956 were tested for cell surface hydrophobicity abilities against xylene, chloroform and ethyl acetate. The isolates were also tested for auto-aggregation and co-aggregation abilities; the optical densities of cell growth were measured after 1, 2, 3 and 4 h of experimental set-up. DNA was extracted from all the four isolates and amplified using PCR with specific primers to detect virulence genes of adhesion collagen protein (ace) and aggregation substances (agg and asa); also, resistance genes of Vancomycin vanA, Vancomycin vanC1 and Vancomycin vanC2/3 were assayed in the four isolates. The isolates showed high hydrophobicity to all solvents: xylene (78-84%), chloroform (68-75%) and ethyl acetate (52-60%). High auto- and co-aggregations ranging from 60 to 70% and from 45 to 56% respectively were observed in the isolates after 4 h of incubation at 37 °C. Some of the tested isolates showed the presence of virulence and resistance genes; however, this does not indicate that these genes are unsafe because their transmission and expression abilities are unknown. Therefore, in this study, the isolates studied are considered safe for use as future probiotics, as revealed from results presented, which generally represents the scanned safety evaluations of the isolates as promising probiotics.

Dephytinizing and Probiotic Potentials of Saccharomyces cerevisiae (NCIM 3662) Strain for Amelioration of Nutritional Quality of Functional Foods

Increase of undigested complexes of phytic acid in food is gaining serious attention to overcome nutritional challenges due to chelation effects. We investigated soil-borne yeast phytase from Saccharomyces cerevisiae (NCIM 3662) for dephytinization of foods, probiotic properties, and process development. The strain produced 45 IU/DCG by cell-bound phytase in an unoptimized medium was increased fourfold (164 IU/DCG) in 12 h using statistical media optimization. The process was scaled-up up to 10-L fermenter scale with increased phytase productivity of 6.4 IU/DCG/h as compared to the lab scale. The strain displayed probiotic characteristics like tolerance to artificial gastric acid conditions, hydrophobicity, autoaggregation, coaggregation, and bile salt hydrolase (BSH) activity. Further, it could dephytinize (removal of phytic acid; an anti-nutritional factor) functional foods like ragi (finger millet) flour, soya flour, chickpea flour, and poultry animal feed. A combination of cell-bound dephytinizing phytase and nutrition-ameliorating probiotic traits of S. cerevisiae (NCIM 3662) presents profound applications in food technology sector.

Diversity and Succession of Microbiota during Fermentation of the Traditional Indian Food Idli

Idli, a naturally fermented Indian food, is prepared from a mixture of rice and black gram (lentil). To understand its microbial community during fermentation, detailed analysis of the structural and functional dynamics of the idli microbiome was performed by culture-dependent and -independent approaches. The bacterial diversity and microbial succession were assessed at different times of fermentation by 16S rRNA amplicon sequencing. Results highlighted that most microbiota belonged to phylum Firmicutes (70%) and Proteobacteria (22%). Denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR) analysis confirmed the diversity and succession involved therein. A culture-dependent approach revealed that the microbially diverse populations were conserved across different geographical locations. The fermentation was primarily driven by lactic acid bacteria as they constitute 86% of the total bacterial population, and genus Weissella emerged as the most important organism in fermentation. The natural microbiota of the grains mainly drives the fermentation, as surface sterilized grains did not show any fermentation. Growth kinetics of idli microbiota and physicochemical parameters corroborated the changes in microbial dynamics, acid production, and leavening occurring during fermentation. Using a metagenomic prediction tool, we found that the major metabolic activities of these microbial fermenters were augmented during the important phase of fermentation. The involvement of the heterofermentative hexose monophosphate (HMP) pathway in batter leavening was substantiated by radiolabeled carbon dioxide generated from d-[1-14C]-glucose. Hydrolases degrading starch and phytins and the production of B vitamins were reported. Moreover, culturable isolates showing beneficial attributes, such as acid and bile tolerance, hydrophobicity, antibiotic sensitivity, and antimicrobial activity, suggest idli to be a potential dietary supplement.IMPORTANCE This is a comprehensive analysis of idli fermentation employing modern molecular tools which provided valuable information about the bacterial diversity enabling its fermentation. The study has demonstrated the relationship between the bacterial population and its functional role in the process. The nature of idli fermentation was found to be more complex than other food fermentations due to the succession of the bacterial population. Further studies using metatranscriptomics and metabolomics may enhance the understanding of this complex fermentation process. Moreover, the presence of microorganisms with beneficial properties plausibly makes idli a suitable functional food.

Isolation of phytase-producing yeasts from rice seedlings for prospective probiotic applications

The yeasts transmitted from seeds to sprouts might be used as probiotics for host plants. To investigate the inheritable yeasts of rice plants for probiotics, the fungal internal transcribed spacer (ITS) regions (ITS1 and ITS2) in rice sprouts were analyzed by Illumina-based sequencing. The fungal genera Candida, Mortierella, Alternaria, Penicillium, and Tomentella were revealed by both ITS1 and ITS2 sequence analysis. The endophytic yeasts were isolated from rice sprouts by yeast selective medium. Compared with the negative controls, inoculation of isolate Y3 released 2.2 folds higher concentration of free phosphate in soybean meal broth. Most of the phytase activities were located in the yeast cell interiors. The shoot lengths, shoot fresh weights, and root fresh weights of inoculated seedlings increased by 35%, 80%, and 60% compared with the control seedlings, respectively. The results suggested that the rice sprouts contained diverse phytase-producing yeasts transmitted from seeds. These yeasts might be adopted as prospective probiotics to improve rice growth by increasing phosphate utilization efficacy.

Aciduric Strains of Lactobacillus reuteri and Lactobacillus rhamnosus, Isolated from Human Feces, Have Strong Adhesion and Aggregation Properties

Human feces were streaked onto MRS Agar adjusted to pH 2.5, 3.0, and 6.4, respectively, and medium supplemented with 1.0% (w/v) bile salts. Two aciduric strains, identified as Lactobacillus reuteri HFI-LD5 and Lactobacillus rhamnosus HFI-K2 (based on 16S rDNA and recA sequences), were non-hemolytic and did not hydrolyze mucin. The surface of Lactobacillus reuteri HFI-LD5 cells has a weak negative charge, whereas Lactobacillus rhamnosus HFI-K2 has acidic and basic properties, and produces exopolysaccharides (EPS). None of the strains produce bacteriocins. Both strains are resistant to several antibiotics, including sulfamethoxazole-trimethoprim and sulphonamides. The ability of Lactobacillus reuteri HFI-LD5 and Lactobacillus rhamnosus HFI-K2 to grow at pH 2.5 suggests that they will survive passage through the stomach. EPS production may assist in binding to intestinal mucus, especially in the small intestinal tract, protect epithelial cells, and stimulate the immune system. Lactobacillus reuteri HFI-LD5 and Lactobacillus rhamnosus HFI-K2 may be used as probiotics, especially in the treatment of small intestinal bacterial overgrowth (SIBO).

Hypocholesterolemic and bioactive potential of exopolysaccharide from a probiotic Enterococcus faecium K1 isolated from kalarei

Bioprospecting of novel probiotic strains especially from unexplored eco-niches has been a continuous practice. Enterococcus faecium K1, an isolate from indigenously fermented milk product kalarei possesses numerous desirable functional attributes. In current study, E. faecium K1 has been used for EPS production, and it yielded 355 ± 0.019 mg/L EPS. EPS demonstrates remarkable hypocholesterolemic, antioxidant, antibiofilm, and emulsification characteristics. EPS is constituted of mannose, glucose and galactose. SEM analysis reveals flake like compact structure of EPS while TEM and X-ray diffractogram confirms the amorphous structure of EPS. FTIR substantiates the functional groups/bonds typical of polysaccharides. Thermal analysis indicates adequate stability of EPS at 237 °C with average weight loss of 22%. E. faecium K1 EPS possesses unique functional bioactivities and physicochemical characteristics, and may potentially be explored for applications in food/pharmaceutical industries.