Document Detail


Effect of process variables on supercritical fluid disruption of Ralstonia eutropha cells for poly(R-hydroxybutyrate) recovery.
MedLine Citation:
PMID:  15575709     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This research focuses on the disruption of the gram-negative bacterium Ralstonia eutropha cells by supercritical CO2 for poly(R-hydroxybutyrate) (PHB) recovery. The variables affecting cell disruption such as drying strategy, type of modifier, and cultivation time, as well as operating pressure, temperature, and repeated release of supercritical CO2 pressure, have been studied. Effect of this disruption technique on PHB molecular mass was also investigated. PHB recovery was examined using a combination of this method and chemical pretreatments. For salt pretreatment, the cells were exposed to 140 mM NaCl and heat (60 degrees C, 1 h). The cells were also exposed to 0.2-0.8% (w/w) NaOH to examine the effect of alkaline pretreatment. Bacterial cells treated in growth phase exhibited less resistance to disruption than nutrient-limited cells in the stationary phase. It was also found that the wet cells could be utilized to recover PHB, but purity of the product was lower than that obtained from freeze-dried cells. Pretreatment with a minimum of 0.4% (w/w) NaOH was necessary to enable complete disruption with two times pressure release. Salt pretreatment was less effective; however, disruption was improved by the application of alkaline shock. The proposed method is economic and comparable with other recovery methods in terms of the percentage of PHB recovery and energy consumption, while it is environmentally more benign.
Authors:
Kianoosh Khosravi-Darani; Ebrahim Vasheghani-Farahani; Seyed Abbas Shojaosadati; Yadollah Yamini
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Publication Detail:
Type:  Comparative Study; Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biotechnology progress     Volume:  20     ISSN:  8756-7938     ISO Abbreviation:  Biotechnol. Prog.     Publication Date:    2004 Nov-Dec
Date Detail:
Created Date:  2004-12-03     Completed Date:  2005-04-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8506292     Medline TA:  Biotechnol Prog     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1757-65     Citation Subset:  IM    
Affiliation:
Department of Chemical Engineering, Tarbiat Modarres University, P.O. Box 14115-143, Tehran, Iran.
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MeSH Terms
Descriptor/Qualifier:
Cell Culture Techniques / methods*
Cell Fractionation / methods*
Cell Proliferation
Chromatography, Supercritical Fluid / methods*
Cupriavidus necator / cytology*,  metabolism*
Factor Analysis, Statistical
Hydroxybutyrates / isolation & purification*,  metabolism*
Polyesters / isolation & purification*,  metabolism*
Pressure
Protons
Temperature
Chemical
Reg. No./Substance:
0/Hydroxybutyrates; 0/Polyesters; 0/Protons; 26063-00-3/poly-beta-hydroxybutyrate

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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