ISOLATION AND CHARACTERIZATION OF POTENTIAL PROBIOTIC YEASTS FROM DIFFERENT SOURCES

objective The main objective of the present study is to isolate yeasts from different environmental sources to investigate their potential probiotic characteristics.Methods Appropriate in vitro assays has been conducted to examine their probiotic potentiality, such as acid and bile salt tolerance, temperature resistance, stimulated GIT tolerance, cell adhesion and cholesterol removal. All the yeast isolates were tested under in vitro conditions.Results In the present study, 20 yeast species have been isolated from different sources, screened and their desirable probiotic properties viz. pH tolerance, bile salt tolerance and thermo-tolerance have been evaluated. Screened yeast isolates treated with gastric juices showed increased survival rate above 60%. A further in vitro study investigates cholesterol removal and it showed increased cholesterol removal rate up to 92%. Exopolysaccharide production was estimated for selected yeast isolates and applications are under investigation.Conclusion Among 20 yeast isolates, 5 isolates showed increased growth under stress tolerance. It can be concluded that the screened yeast isolates LM, MR, GOI, GII2 and WI can serve as promising probiotics in various fields of food industry.Key words:  Acid tolerance; bile tolerance, cholesterol removal, probiotics, yeast

MOLECULAR IDENTIFICATION OF PROBIOTIC YEAST STRAINS AND THEIR CHARACTERIZATION

Objective The objective of the present study was to identify the potential yeast isolates at themolecular level and evaluate their probiotic characteristics.MethodsMolecular characterization was done for 5 potential probiotic yeast strains. In vitro assays have been conducted to evaluate the probiotic properties such as NaCl tolerance, autoaggregation and co-aggregation. Haemolyticactivity, urease activity and cytotoxicity tests were carried out for safety assay during the characterization of yeast strains.ResultsIn this study, the yeast strains viz. LM,MR,GOI,GII2and WI were identified at molecular level and named as Yarrowialipolytica VIT-MN01, Kluyveromyces lactis VIT-MN02, Lipomyces starkeyi VIT-MN03, Saccharomycopsis fibuligera VIT-MN04, Brettanomyces custersianus VIT-MN05 respectively. Maximum autoaggregation and coaggregationwere noted in case of Lipomyces starkeyi VIT-MN03, Saccharomycopsis fibuligeraVIT-MN04, and Brettanomyces custersianus VIT-MN05. In vitro toxicity assay was performed and all the yeast strains showednon-toxic nature.ConclusionFive yeast strains have been studied for their probiotic characteristics and identified at molecular level. Out offive yeast strains, three strains showed maximum adhesion ability,which is a prerequisite for colonization and protection of gastrointestinal tract. All the yeast strains are validated as a safe bioresources because of their non - hemolytic activities and non-production of urease. It can be concluded that the identified yeast strainscan serve as promising probiotics in various fields offood industry

Therapeutic potential of dietary phytochemicals from <i>Drynaria quercifolia</i> to modulate gut microbiome: an <i>in silico</i> approach

Drynaria quercifolia is one of the pioneer medicinal plants which exert many beneficial effects on humans. Fatty acids are hydrophobic ligands that act as membrane substrates, metabolic signalling molecules, and metabolic energy sources. It could enhance the mucus production in the intestine which maintain mucosal homeostasis. The inflammatory responses were also regulated by 5-HT receptors. Serotonin 2 A receptors are G-protein coupled receptors targeted by various types of ligands viz. antidepressants, antipsychotics and anti-migraine drugs. The interaction of mucin protein and fatty acid could increase the antimicrobial activity and anti-inflammatory activity of gut microbiome. In this study, dietary phytochemicals were extracted from D. quercifolia and characterized using GC-MS analysis. The result shows presence of 38 various compounds viz. decanoic acid, indole, and dodecanoic acid and etc., Among the all, dodecanoic acid showed good drug likeness and pharmaceutical properties. Target proteins viz. 3IFB (Intestinal fatty acid binding protein) and 7WC4 (5-hydroxytryptamine receptor 2 A) were docked with dodecanoic acid using Auto dock software. The fatty acids produced in the gut could interact with 3IFB and 7WC4 proteins to maintain intestinal integrity and improved gut-brain function respectively. Dodecanoic acid exhibits the highest binding energy with mutated 3IFB (-6.01) than native whereas 7WC4 native protein showed (-7.3 kal/mol) the highest affinity than mutated protein. Structural changes were predicted by using SOPMA and ProSA. Evaluation results indicate that 3IFB was having more stability, good quality, and enhanced affinity than 7WC4. Further, MD simulations were done for 3IFB to check the stability of protein-ligand complex using WebGro platform. The model was investigated by root mean square deviation and fluctuations. Therefore, dodecanoic acids have been considered as a potential agonists and offer opportunities for developing innovative medications for gastrointestinal diseases. Communicated by Ramaswamy H. Sarma</p