Concomitant yield optimization of tannase and gallic acid by Bacillus licheniformis KBR6 through submerged fermentation : an industrial approach

The present study is concerned with the evaluation of tannase and gallic acid production effi cacy of Bacillus licheniformis KBR6 under diff erent environmental conditions through submerged fermentation. Results have shown that diff erent environmental conditions and mineral sources have diff erential infl uences on tannase and gallic acid production. Highest tannase and gallic acid yield was observed at incubation period of 18 h and 22 h, respectively. At tannic acid concentration of 15 g/l, maximum cell mass (0.75 g/l), cell yield coeffi cient (0.08 g/g), specifi c growth rate (37.5 mg/g/h), tannase yield (16.3 U/g) and specifi c tannase production rate (0.80 U/g/h) were observed, however, at higher tannic acid concentration a decrease in tannase yield and production rate were observed, but gallic acid production increased with increasing tannic acid concentration. Additional carbohydrate sources like glucose, fructose, and lactose showed positive infl uence on enzyme yield. Among the studied nitrogen sources urea and NH4Cl, and of the phosphate sources KH2PO4 showed favourable eff ects on cell growth and simultaneous enzyme and gallic acid production. Temperature of 35 °C was found to be optimum for tannase and gallic acid production. Of all the studied metal ions Ca2+, Mg2+ and Na+ showed positive eff ect whereas, Co2+, Ag2+, Pb2+, Hg2+ showed inhibitory eff ects

Study of nutritional and antibacterial potential of some wild edible mushrooms from Gurguripal Ecoforest, West Bengal, India

222-227Mushrooms are important natural resources concerning human health, nutrition and disease prevention. The present study was conducted for the exploitation of wild edible mushrooms of Gurguripal Ecoforest. The analysis of nutrients in Termitomyces heimii, Astraeus hygrometricus, Leucopaxilus sp., Amanita vaginata, Agaricus campestris, Russula delica, Schizophyllum commune, Pleurotus ostreatus and Cantharellus sp. on dry wt basis showed that these mushrooms were rich in proteins (20.4-38.3%) and carbohydrates (33.2-48.4%), while lipid contents were relatively low (0.8-6.2%). The fibre and ash contents ranged 2.0-18.6% and 2.3-14.9%, respectively. Antibacterial properties of mushroom extracts were studied against some human pathogens like Escherichia coli MTCC118, Shigella flexneri MTCC7061, Staphylococcus aureus MTCC96, Streptococcus faecalis MTCC5383, Salmonella typhi MTCC734, Klebsiella pneumoniae MTCC109, Enterobacter aerogenes MTCC111, Vibrio cholerae MTCC3906, Pseudomonas aeruginosa MTCC741 and Bacillus subtilis MTCC441. Acetone extracts of P. ostreatus and T. heimii showed noticeable antibacterial potentialities against S. aureus and K. pneumoniae, respectively. Biosynthesis of nanoparticles using mushroom extracts was performed to increase the effectiveness of antibacterial potentials. Silver nanoparticles were synthesized using extracts of Volvariella volvacea and applied against E. coli and S. flexneri, which showed inhibition zones of 15 and 18 mm respectively. The silver nanoparticles were also characterized through UV-Visible spectroscopy and FTIR analysis

Thermostable acidic protease production in Aspergillus terreus NCFT 4269.10 using chickling vetch peels

A newly isolated fungus, Aspergillus terreus NCFT4269.10, was employed in both solid state (SSF) and liquid static surface culture (LSSC) for the production of protease using different agro-residues. Among different substrates appraised, chickling vetch peels (CVP) supported the enhanced production of protease both at LSSC and SSF (499.99 ± 11 U/ml; 5266.8 ± 202.5 U/gds, respectively). In the presence of peptone (1%, w/v), leucine (5 mM/100 ml), Fe2+ (1 mM) and riboflavin (10 mg/100 ml) with a medium pH of 5.0 incubated at 30 °C for 96 h, 3-fold higher protease production was achieved in LSSC compared with control. Fermentation kinetics studies revealed that the highest specific growth rate of A. terreus was observed in fermentation medium supplemented with riboflavin (10 mg/100 ml), i.e., 256.45 mg l−1 h−1. The growth-associated coefficient of enzyme production (α) by A. terreus was maximal when protease was produced using Fe2+. Further, the protease was purified to electrophoretic homogeneity and its molecular mass was determined as 23.8 kDa. The present strain suggests the potential utilization of inexpensive agro-residues (CVP) as medium components for the efficient industrial production using LSSC

<span style="font-size:11.0pt;font-family: "Times New Roman","serif";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Keratinase production by <i>Bacillus weihenstephanensis</i> PKD5 in solid-state fermentation and its milk clotting potential</span>

200-207<span style="font-size:11.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">A low cost and energy intensive solid-state fermentation medium was formulated by employing poultry feather for the production of keratinase by Bacillus weihenstephanensis PKD5 following ‘one variable at a time’ (OVAT) and response surface methodology (RSM). After OVAT optimization, four most critical factors were identified with significant increase of enzyme production (2.95-fold). Among them, incubation period, incubation temperature, pH and nitrogen source (ammonium chloride) were further optimized statistically by Box-Behnken RSM. The results of analysis of variance and regression of the second-order model of RSM showed that among the parameters, fermentation time (2.85 d), temperature (34.12<span style="font-size:11.0pt; font-family:Symbol;mso-ascii-font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-hansi-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi;mso-char-type:symbol;mso-symbol-font-family:symbol"="" lang="EN-GB">°C), pH (7.79) and ammonium chloride (0.5%) had the significant influences on keratinase production. Under the optimized conditions, a maximum enzyme production of 164.9 U/g was achieved, which was 3.17-fold higher. During further investigation on milk clotting property, the enzyme had shown the clotting activity of 43.6 SU/mL, suggesting its usefulness as new source of milk-coagulant for cheese making.</span

Dengue virus type 4 evolution and genomics: A bioinformatic approach

330-336Dengue is becoming the most devastating endemic disease in the last few years all over the world. Four serotypes DENV1, DENV2, DENV3 and DENV4 show strong adaptation against host defence. DENV4 is phylogenetically most divergent serotype and highlights the importance of the study about evolution and genomics of DENV4 genome. Overall, study of codon usage pattern at gene level and the effect of mutational bias, natural selection, translational selection and gene length were estimated. A multivariate statistical analysis showed the conservation of codon usage pattern among phylogenetically closely related DENV4 genomes. For compositional constraint, most of the preferred codons in DENV4 genes contain ‘A’ and/or ‘T’ at 3rd position. Moreover, mutational bias and gene length were also functioning for the variation in codon usage. Pyrimidines ending preferred codons were slightly numerous in highly expressed genes, but codon usage bias was higher in non-structural genes than structural one, which was the evidence for the absence of the effect of translational selection on codon usage variation of DENV4 genome. The study is helpful to understand the evolution of DENV4 genome and gradual change in their pathogenicity

<span style="mso-bidi-font-size:12.0pt" lang="EN-GB">Potentialities of newly isolated <i style="mso-bidi-font-style:normal">Bacillus subtilis</i> and <i style="mso-bidi-font-style:normal">Lactobacillus sp</i> for curd preparation and a comparative study of its physico-chemical parameters with other marketed curds </span>

910-918Two Bacillus sp. were isolated from the local fermented milk and identified on the basis 16S rRNA sequence profile as Bacillus subtilis AKL1 and by biochemical process as Lactobacillus acidophilus AKL2. These isolates were <span style="mso-bidi-font-weight: bold">used as fresh inoculums for curd preparation individually and in combinations. Different physico-chemical and therapeutic properties of the newly prepared curd were examined and compared with marketed local (sweet and sour) and branded (Mother Dairy and Thackar) curds. The total hydrolyzed peptides, free amino acids, lactic acid were significantly higher, whereas, total solid, ash content, syneresis and free reducing sugar were lower in the curd prepared by a mixture of AKL1 and AKL2 (0.5:0.5, v/v). The antioxidant activity against ABTS+, DPPH•, OH• and Fe3+ were also higher in the newly formulated curd. Polyphenols (85.5µg/g), flavonoids (12.5µg/g) and free aromatic amino acids contents were also higher in AKL1+AKL2. All these components prevent excess protein oxidation that was revealed by SDS-PAGE. The curd also exhibited potent antimicrobial activity against some entero-pathogens like <i style="mso-bidi-font-style: normal">Clostridium perfringens, <i style="mso-bidi-font-style: normal">Escherichia coli, <i style="mso-bidi-font-style: normal">Shigella dysentery, Vibrio cholerae <span style="background:white;mso-bidi-font-weight:bold;mso-bidi-font-style: italic" lang="EN-GB">and Staphylococcus<i style="mso-bidi-font-style: normal"> aureus. It can be concluded that the combination of these Lactobacillus sp. will be a fruitful inoculum for the preparation of curd having better health promoting effects. </span

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