Kadirvelu Jeevaratnam

Screening of Lactobacillus plantarum isolated from fermented idli batter for probiotic properties

Probiotics are defined as live microorganisms which when administered in adequate amounts confer a health benefit on the host. The objective of this study was to screen eight potential probiotic Lactobacillus plantarum strains from fermented idli batter using in vitro assays such as bile tolerance, acid tolerance, transit tolerance in the upper human gastrointestinal tract, auto-aggregation, co-aggregation, hydrophobicity, susceptibility to various antibiotics, bile salt hydrolase assay, cholesterol assimilation and hemolysis. The isolates were able to tolerate up to 0.3% of bile for 4 to 6 h and pH 2.5, 3.5, 4.5, 6.5, 7.5 and 8.5. The isolates were able to resist growth against gastric and intestinal fluid. The auto-aggregation of the different L. plantarum strains ranged from 65 to 80% in all the isolates. The co-aggregation with pathogens like Listeria monocytogenes (MTCC 657) and Escherichia coli (MTCC 728) ranged from 51 to 64%, however, low levels of co-aggregation were observed in L. plantarum (MTCC 6161) and L. rhamnosus (MTCC 1408) ranging from 32 to 46% and hydrophobicity from 49 to 77%. The isolates showed resistance towards antibiotics like gentamycin, ciprofloxacin, nalidixic acid and norfloxacin. All the isolates showed bile salt hydrolase activity with cholesterol lowering capacity, the highest being 73% by L. plantarum JJ 18. The isolates possessed â-galactosidase activity exhibiting 322 to 1000 MU of enzyme activity. No isolates showed hemolysis activity. Thus, the different L. plantarum isolates exhibited probiotic potential which would attribute beneficial effect to mankind. Key words : Lactobacillus plantarum, probiotics, cholesterol, β-galactosidase.

Bacteriocin activity against various pathogens produced by pediococcus pentosaceus vj13 isolated from idly batter

Bacteriocins, an antimicrobial peptide, is known to have wide spectrum antimicrobial activity against various pathogens. Because they are easily digested in the intestine, they are considered as safe and are widely used as food preservatives. Hence their purification and characterization have attracted considerable attraction, especially for those having activity against human pathogens. In this study, the bacteriocin produced by Pediococcus pentosaceus VJ13 was precipitated with cold acetone and purified by gel permeation chromatography and hydrophobic interaction chromatography. The bacteriocin exhibited antimicrobial activity against various pathogens, like Mycobacterium smegmatis, Klebsiella pneumonia, Clostridium perfringens and Staphylococcus epidermidis. The activity of bacteriocin was lost completely after treatment with protease, which revealed its proteinaceous nature. The bacteriocin was stable up to 100°C and exhibited antilisterial property which is a characteristic feature of class IIa bacteriocins. It was active within the pH range of 2-8 and stable against various chemicals and denaturants. Tricine SDS-PAGE revealed its molecular weight to be 4.0 kDa, where the corresponding activity against Listeria monocytogenes was also noted. Treatment of L. monocytogenes with bacteriocin decreased the viable cell count, and scanning electron microscope analysis revealed membrane pore formation that resulted in the release of intracellular content, suggesting its bactericidal effect.

Molecular characterization of lactobacilli isolated from fermented idli batter

Lactic acid bacteria are non pathogenic organism widely distributed in nature typically involved in a large number of spontaneous food fermentation. The purpose of this study was to characterize the bacteriocinogenic lactobacilli from fermented idli batter which can find application in biopreservation and biomedicine. Eight most promising lactobacilli were chosen from twenty two isolates based on their spectrum of activity against other lactic acid bacteria and pathogens. The eight lactobacilli were characterized based on the various classical phenotypic tests, physiological tests and biochemical tests including various carbohydrate utilization profiles. All isolates were homo fermentative, catalase, and gelatin negative. Molecular characterization was performed by RAPD, 16S rRNA analysis, 16S ARDRA, and Multiplex PCR for species identification. RAPD was carried out using the primer R2 and M13. Five different clusters were obtained based on RAPD indicating strain level variation. 16S rRNA analysis showed 99 to 100% homology towards Lactobacillus plantarum. The restriction digestion pattern was similar for all the isolates with the restriction enzyme AluI. The subspecies were identified by performing Multiplex PCR using species specific primer. Among the five clusters, three clusters were clearly identified as Lactobacillus plantarum subsp. plantarum, Lactobacillus pentosus, and Lactobacillus plantarum subsp. argentoratensis.

solation and Characterization of Pediococcus Pentosaceus from Idly Batter: A Traditional South Indian Fermented Food Source

Lactic acid bacteria (LAB) are protective and generally recognized as safe (GRAS) organisms that are involved in fermentation process. Idly batter is a traditional fermented food source in south India and distribution of LAB varies with source of batter preparation and seasons. Thus, an attempt was made to isolate LAB from idly batter. A total of 40 cocci were obtained out of which 18 exhibit wide spectrum of antimicrobial activity against Gram positive and negative organisms. The antimicrobial activity was lost completely after treatment with protease suggesting bacteriocinogenic in nature. These potent bacteriocinogenic isolates were clustered into four based on the RAPD and further grouped into six based on physiological, and biochemical characterization. One isolate from each group were further characterized using various molecular tools. The 16S rRNA gene sequencing of homofermentative isolates exhibited 98–100% homology with Pediococcus pentosaceus. These isolates obtained from idly batter may have a significant role imposing health benefits.

Extracellularly synthesized ZnO nanoparticles interact with DNA and augment gamma radiation induced DNA damage through reactive oxygen species

The present study proposes a green synthesis of highly stable and biocompatible ZnO nanoparticles (ZnONPs) using ferulic acid as the reductant. The biosynthesized nanoparticles were characterized by UV-visible spectroscopy, photoluminescence spectroscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, atomic mass spectroscopy, energy dispersive X-ray spectroscopy and elemental mapping. The characterization results elucidate the formation of crystalline wurtzite structured acicular shaped ZnONPs. Furthermore, the intricate mechanism of ZnONPs–DNA interaction was studied. The binding affinity and mechanism of ZnONPs with calf thymus-DNA interactions were scrutinized and the conformational changes were analyzed. The results reveal the interaction of ZnONPs with DNA in intercalation mode and the values of the binding constant (K) and Stern–Volmer quenching constant (Ksv) were found to be 5.8 × 105 M−1 and 4.1 × 105 M−1, respectively. Furthermore, gamma radiation induced reactive oxygen species (ROS) generation and DNA damage by ZnONPs were analyzed by various spectrophotometric methods, which unveiled the radiosensitizer role of ZnONPs through the significantly increased generation of ROS. Our current experimental evidence explores the ZnONPs’ dual role capacity as DNA binders as well as radiosensitizers. Based on the present research findings we conclude that ZnONPs can be excellent anticancer agents, warranting in vivo studies.

Optimization of nutritional and non - nutritional factors involved for production of antimicrobial compounds from Lactobacillus pentosus SJ65 using response surface methodology

Bacteriocins from lactic acid bacteria are ribosomal synthesized antibacterial proteins/peptides having wide range of applications. Lactobacillus pentosus SJ65, isolated from fermented Uttapam batter (used to prepare south Indian pan cake), produces bacteriocin having a broad spectrum of activity against pathogens. Optimization studies are of utmost important to understand the source of utilization and the conditions to enhance the production of metabolites. In the present study, an attempt was made to identify the parameters involved for maximal production of antimicrobial compounds especially bacteriocin from the isolate L. pentosus SJ65. Initially, optimal conditions, such as incubation period, pH, and temperature were evaluated. Initial screening was done using methodology one-variable-at-a-time (OVAT) for various carbon and nitrogen sources. Further evaluation was carried out statistically using Plackett-Burman design and the variables were analyzed using response surface methodology using central composite design. The optimum media using tryptone or soy peptone, yeast extract, glucose, triammonium citrate, MnSO4, dipotassium hydrogen phosphate and tween 80 produced maximum bacteriocin activity.

Probiotic Potential of Pediococcus pentosaceus LJR1, a Bacteriocinogenic Strain Isolated from Rumen Liquor of Goat (Capra aegagrus hircus)

ABSTRACT In present study, we evaluated the probiotic potential of three potent antibacterial Pediococcus pentosaceus isolates, viz., LJR1, LJR5, and LJR9 from the rumen liquor of a healthy goat and compared to a commercial probiotic, Lactobacillus rhamnosus GG NCDC 347. All the three isolates exhibited broad-spectrum of antibacterial activity against food borne pathogens. Among the isolates P. pentosaceus LJR1 strain was found to tolerate acid, bile, simulated gastric, and intestinal juice comparable to a standard strain and also showed strong adhesion to the human colon cancer (HCT-15) cells and prevented adhesion of Listeria monocytogenes. Furthermore, the P. pentosaceus LJR1 showed strong anti-inflammatory properties in the LPS-inflamed human peripheral blood mononuclear cells (PBMCs). The P. pentosaceus LJR1 showing potent antibacterial activity and all the desirable attributes of probiotic bacteria can be utilized as a candidate for the development of probiotic foods and deserves to be exploited for human and animal use.

Molecular Characterization of Lactobacilli Isolated from Piper betle L. var. Pachaikodi and Comparative Analysis of the Antimicrobial Effects of Isolate Lactobacillus plantarum KJB23 and Betel Leaves Extract

ABSTRACT Traditionally Piper betle L. leaves have been used in India for fermenting certain foods. In our previous study, while fermenting Uttapam batter along with Piper betle L. var. Pachaikodi leaves led to suppression of gas formation and altered Lactic acid bacteria profile, especially in bacilli isolates compared to those observed in plain Uttapam batter fermentation. Hence, the aim of the present study was to understand the rationale behind these changes through characterization of Lactobacillus isolates from Piper betle L. var. Pachaikodi and also the leaves extracts for antimicrobial activity. Out of 72 isolates obtained from the betel leaves, only 10 isolates were bacilli which were chosen for their molecular characterization and to elucidate their inhibitory effects against major food borne pathogens and gas-forming bacteria and to compare with the effect of betel leaves extract. Random amplified polymorphic DNA (RAPD)-PCR and phenotype analysis was used to differentiate the isolates at strain level, 16S rRNA gene sequence for phylogenetic analysis and species-specific multiplex PCR analysis for sub-species identification. All isolates were identified as Lactobacillus plantarum subsp. plantarum. All Lactobacillus isolates were indigenous to leaf as they were resistant to betel leaves extract and showed maximum activity against some LAB and non-LAB indicator strains except Lactobacillus plantarum MTCC 6160 which was resistant. Among them, KJB23, 36 and 47 were the most effective. Particularly, the isolate KJB23 and ethanolic betal leaf extract showed rivaling inhibitory activity against major food borne pathogens, while dissimilar activity against gas forming bacteria. This study revealed that either Piper betle L. leaf or Lactobacillus strains from the leaves can be valuable for food applications when added to fermented products.

Structural characterization and functional evaluation of an exopolysaccharide produced by Weissella confusa AJ53, an isolate from fermented Uttapam batter supplemented with Piper betle L. leaves

Weissella confusa AJ53 isolated from fermented Uttapam batter supplemented with Piper betle L. leaves produced an exopolysaccharide (EPS) from sucrose. The optimum culture conditions were determined for maximum production. EPS AJ53 was characterized using spectral analysis as an unbranched linear (α-1→6 linked) dextran, homopolymer of D-glucose. Melting and degradation temperatures of EPS AJ53 were 103.84 and 265°C, respectively. EPS AJ53 exhibited antioxidant activities for scavenging of hydroxyl, DPPH, and nitric oxide radicals, and metal ion chelating and poor reducing abilities. A fat binding ability, oil emulsifying activity, and syneresis-prevention activity due to a water holding capacity were demonstrated. Application as an adjunct to provide value addition to food products is indicated. A potent flocculating ability enables EPS AJ53 to be used for water treatment and cryoprotectant applications as an alternative cryoprotective agent. The yield and properties of EPS AJ53 indicate multiple uses.

The effect of Piper betle leaves on lacto-fermentation of idli batter, characterization and applicability of potent isolates in soymilk fermentation

The objectives of this study were to deduce the effect of Piper betle leaves on lactofermentation of the idli batter, characterize the potent lactic acid bacteria (LAB) and elucidate their beneficial properties in soymilk fermentation. Twenty potent LAB isolates (11 bacilli and 9 cocci) showing potent antibacterial activity against food borne pathogens were obtained from the seventy isolates screened. The 20 isolates identified using 16S rRNA and Multiplex PCR, belonged to Lactobacillus plantarum subsp. argentoratensis, Lactobacillus paraplantarum, and Pediococcus pentosaceus. Among the 20 isolates, KJBC11, KJBB56, KJBB37, and KJBC67 exhibited high phytase activity in phytate hydrolysis. The isolates, KJBC67, KJBC06, and KJBB56 were used in soymilk fermentation which showed considerable reduction in the polyphenol content and trypsin inhibitory activity. The isolates KJBB37 and KJBC04 showed about 56% DPPH scavenging activity in LAB fermented soymilk compared to unfermented soymilk. Thus, this study provides the beneficial potentials of LAB isolates.