ABSTRACT
Lactococcus lactis (L. lactis)a probiotics microorganism having wide range of benefits on human health, and also protects the body from pathogenic microorganism. This study was conducted to determine the co-culture effect with the probiotic strain L. lactis (MTCC440) on Salmonella enterica serovar Typhi (S.Typhi). The existing problem was to determine the individual growth of both strains during co-culture. Growth kinetics study was performed and observed for 28â¯h and used to determine specific growth rate of S. Typhi under co-culture study. In growth kinetics study maximum specific growth rate (µ) of S. Typhi under monoculture and co-culture study was achieved 0.695 h-1 and 0.35 h-1 respectively. The maximum cell mass of L. lactis and S. Typhi was obtained 0.15â¯g/L and 0.18â¯g/L respectively. In co-culture study, L. lactis was found effective for the inhibition of 73% growth of S. Typhi due to lactic acid production.
Subject(s)
Lactococcus lactis/growth & development , Lactococcus lactis/physiology , Probiotics/pharmacology , Salmonella typhi/drug effects , Salmonella typhi/growth & development , Antibiosis , Biomass , Carbohydrate Metabolism , Cells, Cultured , Coculture Techniques/methods , Kinetics , Lactic Acid/pharmacologyABSTRACT
BACKGROUND: Penicillin G amidase (PGA) (EC 3.5.1.11) are enzymes that are mainly involved in the synthesis of semi-synthetic }-lactam antibiotics. Soluble PGA is costly and lacks long term operational stability. We revised most of the patents related to Penicillin G amidase (PGA) immobilization in the section "Recent Patents on Immobilized Penicillin G Amidase". OBJECTIVE: The aim of this work was to study comparative biochemical property of PGA enzyme immobilized in two hydro-gel beads - Ca-alginate and alginate+chitosan hybrid and morphologically characterised by SEM. METHODS: PGA immobilized in alginate+chitosan hybrid bead shows high pH and thermal stability. Km, Vmax and Effectiveness factor (1) value of free PGA were 56.19 mg/ml, 1.786 U/ml and 1, respectively. These parameters for PGA immobilized alginate beads were 64.84 mg/ml, 0.781U/ml and 0.437, respectively and for PGA immobilized alginate+chitosan hybrid beads were 87.08 mg/ml, 0.622 U/ml and 0.348, respectively. RESULTS: Immobilized PGA on alginate+chitosan hybrid beads gave the highest thermal stability, reusability and storage stability than alginate immobilized PGA. CONCLUSION: The entrapment of PGA on alginate+chitosan hybrid beads revealed several advantages and could be used in 6APA (6- aminopenicillanic acid) production.
Subject(s)
Alginates/chemistry , Chitosan/chemistry , Hydrogel, Polyethylene Glycol Dimethacrylate/chemistry , Penicillin Amidase/chemistry , Penicillin G/chemistry , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , Hydrogen-Ion Concentration , Patents as Topic , Penicillanic Acid/analogs & derivatives , Penicillanic Acid/chemistryABSTRACT
Equilibrium unfolding of A. niger RNase with chemical denaturants, for example GuHCl and urea, and thermal unfolding have been studied as a function of pH using fluorescence, far-UV, near-UV, and absorbance spectroscopy. Because of their ability to affect electrostatic interactions, pH and chemical denaturants have a marked effect on the stability, structure, and function of many globular proteins. ANS binding studies have been conducted to enable understanding of the folding mechanism of the protein in the presence of the denaturants. Spectroscopic studies by absorbance, fluorescence, and circular dichroism and use of K2D software revealed that the enzyme has α + ß type secondary structure with approximately 29% α-helix, 24% ß-sheet, and 47% random coil. Under neutral conditions the enzyme is stable in urea whereas GuHCl-induced equilibrium unfolding was cooperative. A. niger RNase has little ANS binding even under neutral conditions. Multiple intermediates were populated during the pH-induced unfolding of A. niger RNase. Urea and temperature-induced unfolding of A. niger RNase into the molten globule-like state is non-cooperative, in contrast to the cooperativity seen with the native protein, suggesting the presence of two parts/domains, in the molecular structure of A. niger RNase, with different stability that unfolds in steps. Interestingly, the GuHCl-induced unfolding of the A state (molten globule state) of A. niger RNase is unique, because a low concentration of denaturant not only induces structural change but also facilitates transition from one molten globule like state (A(MG1)) into another (I(MG2)).
