Structural and biocompatibility properties of dextran from Weissella cibaria JAG8 as food additive.

Dextran produced from Weissella cibaria JAG8 was purified and characterized. The molecular mass of dextran as determined by the gel filtration and copper bicinchoninate method was approximately, 800 kDa. Monosaccharide analysis revealed that the polysaccharide comprised only glucose units. Dynamic light scattering study confirmed the mono-disperse nature of dextran with hydrodynamic radius of 900 nm. Surface morphology study of dextran by scanning electron microscopy showed the porous web like structure. Cytotoxicity studies on human cervical cancer (HeLa) cell line showed non-toxic and biocompatible nature of dextran. The relative browning for dextran from W. cibaria JAG8 was similar to commercial prebiotic Nutraflora P-95 and 3-fold lower than Raftilose P-95. Synthesis of dextran by dextransucrase treated, sucrose-supplemented skimmed milk revealed the promising potential of dextran as a food additive.

Purified dextransucrase from Pediococcus pentosaceus CRAG3 as food additive.

The extracellular crude dextransucrase (0.67 U/mg) from P. pentosaceus CRAG3 (GenBank accession number JX679020) after PEG-1500 fractionation gave specific activity, 20.0 U/mg which by gel filtration resulted in 46.0 U/mg. The purified dextransucrase displayed molecular size of approximately, 224 kDa. The optimum assay conditions for dextransucrase activity were 5% sucrose in 20 mM sodium acetate buffer (pH 5.4) and 30 degrees C. The dextransucrase was stable up to 40 degrees C and at pH range of 5.4-7.0. The metal ions such as Co2+, Ca2+, Mg2+ and Zn2+ stimulated the dextransucrase activity by 56, 44, 14 and 12%, respectively. It was most stable at -20 degrees C with half-life of 307 days. Amongst various additives used, glycerol and Tween 80 provided significant stability to the enzyme with half-life 15.5 and 85.5 h, respectively as compared to control (6.9 h). The solidification of sucrose supplemented milk by purified dextransucrase due to dextran synthesis displayed its application as additive for improving the texture of dairy products.

Genome-guided approaches and evaluation of the strategies to influence bioprocessing assisted morphological engineering of Streptomyces cell factories.

Streptomyces genera serve as adaptable cell factories for secondary metabolites with various and distinctive chemical structures that are relevant to the pharmaceutical industry. Streptomyces' complex life cycle necessitated a variety of tactics to enhance metabolite production. Identification of metabolic pathways, secondary metabolite clusters, and their controls have all been accomplished using genomic methods. Besides this, bioprocess parameters were also optimized for the regulation of morphology. Kinase families were identified as key checkpoints in the metabolic manipulation (DivIVA, Scy, FilP, matAB, and AfsK) and morphology engineering of Streptomyces. This review illustrates the role of different physiological variables during fermentation in the bioeconomy coupled with genome-based molecular characterization of biomolecules responsible for secondary metabolite production at different developmental stages of the Streptomyces life cycle.

Process development for the production of bioethanol from waste algal biomass of Gracilaria verrucosa.

The algal biomass of different species of Gracilaria were collected from coasts of Orissa and Tamil Nadu, India and characterized biochemically. Among various species, G. verrucosa was found to be better in terms of total carbohydrate content (56.65%) and hence selected for further studies. The agar was extracted from algal biomass and the residual pulp was enzymatically hydrolyzed. The optimization of algal pulp hydrolysis for various parameters revealed a maximum sugar release of 75.8mg/ml with 63% saccharification yield. The fermentation of enzymatic hydrolysate of algal pulp was optimized and 8% (v/v) inoculum size, 12h inoculum age, pH 5.0 were found to be optimum parameters for maximum ethanol concentration (27.2g/L) after 12h. The process of enzymatic hydrolysis and fermentation were successfully scaled up to 2L bioreactor scale.

Recovery and purification of oligosaccharides from copra meal by recombinant endo-ß-mannanase and deciphering molecular mechanism involved and its role as potent therapeutic agent.

Production of manno-oligosaccharides (MOSs) from pretreated and defatted copra meal (dFCO) hydrolysis was achieved by endo-mannanase. Structural characterization of dFCO by FT-IR and NMR exhibited resemblance with galactomannan. The time-dependent hydrolysis of dFCO by recombinant endo-ß-(1 → 4)-mannanase of Clostridium thermocellum by TLC and HPAEC displayed the release of mannose and MOSs mannobiose and mannotriose. Purified MOSs yielded 40 % mannobiose and 18 % mannotriose confirmed by mass spectroscopy which showed mannobiose (m/z = 365) and mannotriose (m/z = 527). The homology based structural analysis of catalytic endo-mannanase (CtManT) showed the catalytic core composed of Glu181 and Glu300 acting as acid/base and Glu288 as a nucleophile during galactomannan hydrolysis. Sub-site mapping of CtManT exhibited two aglycone and four glycone sites at cleavage sites existing on either side of ß-(1 → 4)-linkage of galactomannan. Isolated MOSs displayed potential prebiotic characteristics and supported higher growth of probiotic Lactobacillus acidophilus and Bifidobacterium infantis than with standard inulin. Moreover, MOSs displayed over 97 % tolerance to simulated gastric juice, intestinal fluid, and α-amylase proving its potential as a stable prebiotic over inulin. In vitro cytotoxicity assay of MOSs (500 µg/mL) on human epithelial colorectal adenocarcinoma cell line (HT-29) demonstrated 60 % decreased viability of cells after 48 h displaying anti-tumorigenic property.

Probiotic Potential of Pediococcus pentosaceus CRAG3: A New Isolate from Fermented Cucumber.

A novel strain of lactic acid bacterium isolated from fermented cucumber was selected due to its high glucansucrase activity. It was identified on the basis of 16S rRNA sequence analysis as Pediococcus pentosaceus CRAG3 (GenBank accession number JX679020). The isolate was round shaped, Gram positive, and catalase negative displaying typical features of lactic acid bacterium. It produced 145 ± 3.27 mg lactic acid per ml of cell-free supernatant. It showed ability to ferment carbohydrates such as sucrose, dextrose, and arabinose; showed resistance to antibiotics such as ciprofloxacin, kanamycin, vancomycin; displayed acid production in triple sugar iron agar test and non-motile nature. Interestingly, the isolate also displayed potential probiotic properties such as hydrophobicity, autoaggregation, coaggregation, and in vitro cell adhesion ability. It exhibited resistance against lysozyme and simulated gastric juice at pH 3.0 with 75 and 58% survival, respectively. It also showed tolerance toward 0.3%, w/v bile salts with 73% survival and ability to deconjugate bile salts. The isolate exhibited antibacterial activity and ability to utilize prebiotics such as inulin and raffinose. These results indicate both probiotic property and glucansucrase-producing ability of P. pentosaceus CRAG3.

Novel dextran from Pediococcus pentosaceus CRAG3 isolated from fermented cucumber with anti-cancer properties.

The porous branched dextran of molecular mass 2.93 × 10(5) Da with 50% overall yield (4.5mg/ml) was produced from Pediococcus pentosaceus CRAG3 (GenBank ID: JX679020), a novel isolate from fermented cucumber. It contained glucose monomers linked through 75% α-(1,6) linkage with 25% (α-1,3) branching as displayed by spectroscopic analysis. The peak analysis showed α-(1,3) branching after every five glucose units of main chain. In vitro cytotoxicity analysis of dextran displayed anti-cancer activity against cervical cancer (HeLa) and colon cancer (HT29) cell lines opening new horizons in its pharmaceutical applications. Dextran showed enhanced growth of macrophage lines revealing its biocompatible nature.

Scale up of dextran production from a mutant of Pediococcus pentosaceus (SPAm) using optimized medium in a bioreactor

The mutant of Pediococcus pentosaceus (SPAm) produced earlier by UV-mutagenesis exhibiting higher dextransucrase activity as compared to wild-type was used. The generated mutant SPAm gave 12.2 mg/ml, a 20 percent higher dextran than wild-type. Response surface methodology was carried out for further enhancement of dextran production. To enhance dextran production by the mutant SPAm, Plackett-Burman Design and a 2² full factorial Central Composite Design was employed. After response optimization, the optimum concentration of sucrose and yeast extract was 5.115 percent (w/v) and 0.635 percent (w/v), respectively. The experimental values of dextran 36.0 mg/ml at flask level and 35.0 mg/ml at bioreactor level were in good agreement with the predicted value of 40.8 mg/ml. The increase in dextran production by the mutant SPAm using the optimized medium was 3 fold higher as compared to unoptimized medium.