Fortification of orange juice with microencapsulated Kocuria flava Y4 towards a novel functional beverage: Biological and quality aspects.

To commercialize functional foods, probiotics must exhibit high resistance and acceptable stability under various unfavorable conditions to maintain the quality of fruit juices. This study will provide an insight into fortification of orange juice with a plant probiotic Kocuria flava Y4 by microencapsulation. Therefore, this study investigated the colony release, physicochemical and phytochemical parameters, and antioxidant activity of the orange juice exposed to microencapsulated probiotics and the one without probiotics (control). Evaluation of orange juice on the growth of probiotic bacteria showed that the fortification with alginate and psyllium micro-particles showed highest encapsulation efficiency (99.01%) and acceptable viability of probiotic cells (8.12 ± 0.077 CFU/mL) during five weeks storage at 4 °C. The morphology and functional properties of beads was studied by SEM, Zeta-potential and FTIR analysis. The sucrose and organic acids concentrations decreased significantly during fortification period (0-72 h) except ascorbic acid. Furthermore, glucose, pH, acidity, TSS were maintained. The results affirm the suitability and feasibility of developing a plant probiotic beverage using orange juice by encapsulation method.

Alleviation of dental caries by use of isolated potential probiotic and its characterization.

Streptococcus mutans plays a major role in biofilm formation and pathogenic bacterial adhesion. Here we investigated the abilities of our isolates from diverse conventional sources to characterize the beneficial bacteria for inhibition of S. mutans. Enterobacter cloacae PS-74, a beneficial bacteria isolated from yoghurt, is gram negative, rod shaped, and resistant to acid, bile salt, and amylase. PS-74 cell-free supernatants (CFS) demonstrated highest zone of inhibition of 29 ± 1.7 mm. Further, the minimum inhibitory concentration (MIC) value of CFS PS-74 was recorded to be 10 µL and its minimum bactericidal concentration (MBC) value was found to be 15µL which led to 99.9% log reduction of S. mutans. Moreover, the biofilm formation was reduced by 84.91% at MIC15 of CFS PS-74 which alleviate the dental caries formation by S. mutans. This is the first report on E. cloacae PS-74, which was studied for its probiotic properties to inhibit S. mutans MTCC-890 due to the production of organic acids and employed in oral treatment.

Probiotic Characterization of Indigenous Kocuria flava Y4 Strain Isolated from Dioscorea villosa Leaves.

This aim of the study was to isolate and screen potential probiotics from Dioscorea villosa leaves. The potential isolate Y4 was obtained from the Dioscorea villosa leaves, and its ability to grow in a medium containing high NaCl concentrations (2-10%) indicated its negative hemolytic activity. Furthermore, Y4 demonstrated inhibitory activity against human pathogens, such as Klebsiella pneumonia, Staphylococcus aureus, Citrobacter koseri, and Vibrio cholerae, as well as towards a plant pathogen isolate OR-2 (obtained from Citrus sinensis). Some biologically important functional groups of Y4 metabolites, such as sulfoxide; aliphatic ether; 1, 2, 3-trisubstituted, tertiary alcohol: vinyl ether; aromatic amine; carboxylic acid; nitro compound; alkene mono-substituted; and alcohol, were identified through FTIR analysis. The 16S rRNA sequencing and subsequent phylogenetic tree analysis indicated that Y4 and OR-2 are the closest neighbors to Kocuria flava (GenBank accession no. MT773277) and Pantoea dispersa (GenBank accession no. MT766308), respectively. The potential isolate Y4 was found to exhibit adhesion, auto-aggregation, co-aggregation, and weak biofilm activity. It also exhibited a high level of antimicrobial activity and antibiotic susceptibility. The safety of K. flava Y4 isolate, which is proposed to be a probiotic, was evaluated through acute oral toxicity test and biogenic amine production test. Moreover, the preservation potential of isolate Y4 was assessed through application on fruits under different temperatures. Thus, our results confirmed that Kocuria flava Y4 is a prospective probiotic and could also be used for the preservation of fruits.

Purification and Optimization of Extracellular Lipase from a Novel Strain Kocuria flava Y4.

The exogenous lipolytic activities of Kocuria sp. have been recognized earlier but the genus further contains many more unexplored strains. In this study, the extracellular lipase activity of Kocuria flava Y4 (GenBank accession no. MT773277), isolated from Dioscorea villosa during our previous study, was regulated by different physicochemical parameters, such as pH, temperature, shaking speed, and incubation time. For efficient immobilization of the extracellular lipase, 4% sodium alginate, 50 mL of 25 nM CaCl2.2H2O solution, and 15 min. Hardening time of gel beads in calcium chloride was used. For the first time, K. flava Y4 lipase was purified using ammonium sulphate precipitation followed by dialysis and DEAE-Sepharose anion exchange chromatography with Sepharose-6B gel filtration chromatography, yielding ∼15-fold purified lipase with a final yield of 96 U/mL. The SDS-PAGE of purified lipase displayed a single strong band, indicating a monomeric protein of 45 kDa. At a temperature of 35°C and pH 8, the purified lipase showed maximum hydrolytic activity. Using p-nitrophenyl acetate (p-NPA) as the hydrolysis substrate, the values of K m and V max derived from the Lineweaver-Burk plot were 4.625 mM and 125 mol/min-1mg-1, respectively.

Mycoremediation and toxicity assessment of textile effluent pertaining to its possible correlation with COD.

Globally, textile industries are one of the major sectors releasing dye pollutants. This is the first report on the positive correlation between toxicity and chemical oxygen demand (COD) of textile effluent along with the proposed pathway for enzymatic degradation of acid orange 10 using Geotrichum candidum within a very short stretch of time (18 h). Removal efficiency of this mycoremedial approach after 18 h in terms of chemical oxygen demand, biological oxygen demand, total suspended solids, salinity, color and dye concentration in the treated effluent reached to 98.5%, 56.3%,73.2%, 64%, 89% and 87% respectively. Also there was a decrease in pH of the treated effluent. FTIR analysis of the treated effluent confirmed biodegradation. The LCMS analysis showed the degradation of acid orange 10, which was confirmed by the formation of two biodegradation products, 7-oxo-8-iminonapthalene-1,3-disulfonate and nitrosobenzene, which subsequently undergoes stepwise hydrogenation and dehydration to form aniline via phenyl hydroxyl amine as intermediate. The X-ray diffraction studies showed that heavy metal content in the treated effluent has reduced along with decrease in % crystallinity, indicating biodegradation. The connection between toxicity and COD was also inveterated using Pearson's correlation coefficient. Further the toxicological studies indicated the toxicity of raw textile effluent and relatively lower toxic nature of metabolites generated after biodegradation by G. candidum.

Potential Antimicrobial Peptides Elucidation from the Marine Bacteria.

In recent years, excessive use of antibiotics has been raising its head to a serious problem all around the world, as pathogens become drug-resistant and create challenges to the medical field. This failure of the most potent antibiotics that kill pathogens increases the thirst for researchers to look for another way of killing pathogens. It has led to the findings of antimicrobial peptide, which are the most potent peptides to destroy pathogens. This review gives special emphasis to the usage of marine bacteria and other microorganisms for antimicrobial peptide (AMP), which are eco-friendly as well as a developing class of natural and synthetic peptides with a wide spectrum of targets to pathogenic microbes. Consequently, a significant attention has been paid mainly to (i) the structure and types of antimicrobial peptides and (ii) mode of action and mechanism of antimicrobial peptide resistance to pathogens. In addition to this, the designing of AMPs has been analyzed thoroughly for reducing toxicity and developing better potent AMP. It has been done by the modified unnatural amino acids by amidation to target the control of biofilm and persister cells.

Degradation of dyes by fungi: an insight into mycoremediation.

Currently, globalization, urbanization and industrialization have led to several environmental issues. In many industries, particularly in textile industries, the extensive use of synthetic dyes has increased. Dye is an integral element used to impart color to textile materials. Wastes generated during the processing and treatment of the dye contain inorganic and organic compounds that are hazardous, thereby posing a serious threat to the ecosystem. It is therefore important to implement cost-efficient and successful measures against these emissions in order to preserve habitats and natural resources. In this context, biodegradation by fungi or mycoremediation of dyes using potential fungi is a fairly inexpensive and environmental friendly method for decomposing or mineralizing barely or less decaying dye compounds. Fungi play a crucial role in degrading and decolorizing organic dyes by enzymes and processes such as absorption, adsorption and aggregation of effluent colorants. The factors affecting the decolorization and biodegradation of dye compounds through fungal bioremediation, such as pH, temperature, dye concentration, agitation, effects of carbon and nitrogen sources, dye structure, enzymes, electron donor and redox mediators are discussed in this review. The review also includes a summary on the mechanism and kinetics of dye degradation as well as recent advances and future perspectives in mycoremediation of dyes.