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Journal des bioprocédés et des biotechniques

ISSN: 2155-9821

Accès libre
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Volume 1, Problème 1 (2011)

article de recherche

Chemical Synthesis, Characterization and Bioactivity Evaluation of Hydroxyapatite Prepared from Garden snail (Helix aspersa)

Anjuvan Singh and K. M. Purohit

A novel attempt is made to convert the calcium carbonate skeleton of widely available garden snail shell (Helix aspersa) to hydroxyapatite based bioceramics. The snail shell was found to decompose within 8500C to all the carbonate phases. The calcined snail shells were then treated with acids followed by different chemicals in ammoniacal media maintaining proper stoichemetry to produce fine Hydroxyapatite (HAP) as filter cake with Ca/P molar ratio of 1.67. The dried HAP powder was extremely pure with specific surface area of 15m2/g. The different characterization techniques were adopted both for calcined snail shell and HAP synthesized like X-ray Diffraction (XRD), Thermal Analysis (DTA/TGA), Fourier Transform Infra red Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The surface area and the particle size, of the HAP powder prepared by chemical precipitation route, were also determined by BET and Malvern particle size analyzer respectively. The synthesized powder was soaked in stimulated body fluid (SBF) medium for various periods of time in order to evaluate its bioactivity. The changes of the pH of SBF medium were measured. High bioactivity of prepared HAP powder due to the formation of apatite on its surface was observed. 
article de recherche

Anthocyanin; Egg plant; Response surface methodology; Box-Behnken design

Thirunavukkarasu Arunachalam and Nithya Rajarathinam

 The study investigated the parameter optimization for anthocyanin extraction from egg plant (Solanum melongena) with the approach response surface methodology. Extractions were carried out using acid–ethanol with the temperature range (60–90°C), time (30–90 min) and solid–liquid ratio (1:15–1:30). Three level three factor Box-Behnken design was followed to observe the anthocyanin yield for the studied parameters. The maximum yield of anthocyanin was observed at the temperature 76.5°C in 70 min in the ratio of 1:26.

article de recherche

Response Surface Methodology for Mycoprotein Production by Fusarium Venenatum ATCC 20334

S. M. Hosseini and K. Khosravi-Darani

In this research, the effect of process variable on yield (%w/w protein per biomass) of mycoprotein production by Fusarium venenatum ATCC 20334 in surface culture evaluated. A face centered central composite design (FCCD) was employed to determine maximum protein production at suitable initial concentration of date juice (as a carbon and energy source), nitrogen concentration and seed size. Analysis of variance showed that the contribution of a quadratic model was significant for the response. The optimal condition for mycoprotein production contains 20 g/l of date juice, 4.48 g/l of nitrogen source and 12.97% (v/v) of seed size. In these conditions, 46.48 ± 0.2% (w/w) protein was obtained in the dried cell weight. Heat treatment of fungal biomass at 64 -65˚C for 20-30 min reduced the RNA content to an acceptable level for human food grade products. Finally, after reduction of ribonucleic acid contents of mycoprotein, the amino acids and fatty acids profiles of product were determined. 
article de recherche

A Dehydrogenase Activity Test for Monitoring the Growth of Streptomyces Venezuelae in a Nutrient Rich Medium

T. J. Burdock, M.S. Brooks and A.E. Ghaly

 Jadomycin is a novel antibiotic that has shown activities against bacteria, yeasts and fungi as well as cytotoxic properties to cancer cells. Because of the wide range of its inhibitory actions, jadomycin shows promise as a novel antibiotic and cancer treatment drug. Streptomyces venezuelae are aerobic bacteria that are capable of producing jadomycin when shocked by alcohol in a nutrient deprived amino acid rich medium. The size of the bacterial population that is transferred from the growth medium to the production medium can significantly affect the jadomycin yield. Therefore, the number of transferred bacteria must be accurately measured. In this study, a dehydrogenase activity measurement test was developed for S. venezuelae using triphenyl tetrazolium chloride (TTC) to measure the cell growth and activity in maltose-yeast extract-malt extract (MYM) broth. The dehydrogenase activity was determined by measuring the visible color changes of the TTC to triphenyl formazan (TF). The test conditions which included extraction solvent, number of extractions, incubation time, incubation temperature and medium pH were evaluated. The results showed that the triphenyl formazan was related to the number of cells. Methanol was better able to permeate the cells and extract higher amount of TF than ethanol. The amount of TF increased with the number of extractions for both solvents. A lower medium pH and/or lower temperature produced the highest amount of TF. The best test conditions that produced the highest TF yield were three extractions using methanol after an incubation time of 1 hour at a temperature of 30ºC and a medium pH of 6. 

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