Isolation,Identification of <Emphasis Type="Italic">Lactobacillus mucosae</Emphasis> AN1 and its Antilisterial Peptide Purification and Characterization

Lactobacillus mucosae strain AN1 isolated from sheep milk and characterized for its probiotic suitability. In vitro evaluation of critical gut endurance properties of this strain were assessed by different screening methods such as bile salt, gastric acid, lysozyme tolerance assays, hemolytic, cholesterol reduction properties, and HT-29 cell line adhesion assay. Antibacterial peptide from this strain was purified using ammonium sulphate precipitation, gel filtration chromatography and reverse-phase HPLC. The molecular mass of peptides was determined by Tricine-SDS-PAGE and confirmed by matrix-assisted laser desorption ionization-time of flight mass spectroscopy (MALDI-TOF-MS). Purified peptide was named as AN1 having a molecular mass of 10.66 kDa. Helical structures of peptide were determined using circular dichroism spectroscopy. Stability of peptide AN1 towards different parameters such as pH, temperature, organic solvents, proteolytic, and glycolytic enzymes was also analyzed.     

Optimization of fermentation conditions for the production of ethanol from sago starch using response surface methodology

The quantitative effects of temperature, pH and time of fermentation were investigated on simultaneous saccharification and fermentation (SSF) of ethanol from sago starch with glucoamylase (AMG) and Zymomonas mobilis ZM4 using a Box–Wilson central composite design protocol. The SSF process was studied using free enzyme and free cells and it was found that with sago starch, maximum ethanol concentration of 70.68 g/l was obtained using a starch concentration of 140 g/l, which represents an ethanol yield of 97.08%. The optimum conditions for the above yield were found to be a temperature of 36.74 °C, pH of 5.02 and time of fermentation of 17 h. Thus by using the central composite design, it is possible to determine the accurate values of the fermentation parameters where maximum production of ethanol occurs.     

Optimizing medium constituents and fermentation conditions for citric acid production from palmyra jaggery using response surface method

The quantitative effects of pH, temperature, time of fermentation, sugar concentration, nitrogen concentration and potassium ferrocyanide on citric acid production were investigated using a statistical experimental design. It was found that palmyra jaggery (sugar syrup from the palmyra palm) is a suitable substrate for increasing the yield of citric acid using Aspergillus niger MTCC 281 by submerged fermentation. Regression equations were used to model the fermentation in order to determine optimum fermentation conditions. Higher yields were obtained after optimizing media components and conditions of fermentation. Maximum citric acid production was obtained at pH 5.35, 29.76 °C, 5.7 days of fermentation with 221.66 g of substrate/l, 0.479 g of ammonium nitrate/l and 2.33 g of potassium ferrocyanide/l.     

Coimmobilized whole cells of Pseudomonas reptilivora and Micrococcus glutamicus in calcium alginate gel for the production of L-glutamic acid

A novel method of coimmobilized whole cells of Pseudomonas reptilivora and Micrococcus glutamicus, entrapped in calcium alginate beads have been used for the production of L-glutamic acid in a single stage fermentation process, using selected production medium enriched with glucose as substrate. The results obtained were compared with the L-glutamic acid production by free cells of Micrococcus glutamicus and by mixed culture of Pseudomonas reptilivora and Micrococcus glutamicus. The yield of glutamic acid obtained with mixed culture is relatively more than that the yield obtained with Micrococcus glutamicus alone. The properties of coimmobilized whole cells of Pseudomonas reptilivora and Micrococcus glutamicus in calcium alginate gel matrix have been investigated thoroughly and compared with those of free cells under most suitable conditions of fermentation.     

Partial purification and characterization of bacteriocin produced by Enterococcus faecalis DU10 and its probiotic attributes

A novel bacteriocin produced by avian duck isolated lactic acid bacterium Enterococcus faecalis DU10 was isolated. This bacteriocin showed a broad spectrum of antibacterial activity against important food-borne pathogens and was purified by size exclusion chromatography followed by reverse-phase high-performance liquid chromatography in a C-18 column. Tricine–SDS PAGE revealed the presence of a band with an estimated molecular mass of 6.3?kDa. The zymogram clearly linked the antimicrobial activity with this band. This result was further confirmed by mass-assisted laser desorption ionization time-of-flight mass spectrometry, since a sharp peak corresponding to 6.313?kDa was detected and the functional groups were revealed by Fourier transform infrared spectroscopy. Bacteriocin DU10 activity was found sensitive to proteinase-K and pepsin and partially affected by trypsin and α-chymotrypsin. The activity of bacteriocin DU10 was partially resistant to heat treatments ranging from 30 to 90°C for 30?min. It also withstood a treatment at 121°C for 10?min. Cytotoxicity of bacteriocin DU10 by methyl-thiazolyl-diphenyl-tetrazolium bromide assay showed that the viability of HT-29 and HeLa cells decreased 60?±?0.7% and 43?±?4.8%, respectively, in the presence of 3,200?AU/mL of bacteriocin. The strain withstood 0.3% w/v of bile oxgall and pH 2 affected the bacterial growth between 2 and 4?hr of incubation. Adhesion properties examined with HT-29 cell line showed 69.85% initial population of strain E. faecalis DU10, which was found to be strongly adhered to this cell line. These results conclude bacteriocin DU10 may be used as a potential biopreservative and E. faecalis DU10 may be used as a potential probiont to control Salmonella infections.     

Purification of α-amylase from Bacillus licheniformis by chromatofocusing and gel filtration chromatography

A combination of chromatofocusing and gel filtration chromatography resulted in a simple purification of -amylase from Bacillus licheniformis. The purification was approximately 77-fold. Identification of the purity was established by SDS–PAGE. Molecular weight and isoelectric point of the purified enzyme were 58 kDa and 7.18 respectively. Western blot analysis confirms the specificity of antibody raised against purified -amylase.     

Simultaneous saccharification and fermentation of pretreated sugar cane leaves to ethanol

The simultaneous saccharification and fermentation (SSF) of pretreated sugar cane leaves to produce ethanol using a cellulolytic enzyme complex from Trichoderma reesei QM 9414 and Saccharomyces cerevisiae NRRL-Y-132 was optimized. Enzymic saccharification parameters were evaluated prior to SSF studies. A 92% conversion of 2·5% substrate (alkaline hydrogen peroxide pretreated) to sugars was achieved at 50°C and pH 4·5, using T. reesei cellulase (40 FPU/g substrate), in 48 h. The pretreated substrate was then subjected to an SSF process using the cellulase complex and S. cerevisiae cells. Optimization of the SSF system is described.     

Optimization of medium constituents and fermentation conditions for the production of L-Glutamic acid by the coimmobilized whole cells of Micrococcus glutamicus and Pseudomonas reptilivora

Statistical experimental design was used to optimize medium constituents and the conditions of fermentation, viz., temperature, pH?and the time of fermentation. Higher yields of L-glutamic acid (37.1?kg/m³) was obtained after optimizing medium components and the conditions of fermentation. The optimal levels of medium components were: 61.5575?kg/m³ glucose, 7.3272?kg/m³ urea and 1.783?μg/dm³ biotin. The optimum productivity was achieved using optimized medium at the fermentation temperature of 33.7?°C, initial pH?7.74, and at the time of fermentation of 58.4?h.     

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Author Index