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Enhanced di-rhamnolipid production with an indigenous isolate Pseudomonas aeruginosa J16

Paper ID Volume ID Publish Year Pages File Format Full-Text
35577 45096 2008 6 PDF Available
Title
Enhanced di-rhamnolipid production with an indigenous isolate Pseudomonas aeruginosa J16
Abstract

A newly isolated indigenous strain Pseudomonas aeruginosa J16 was able to produce a glycolipid biosurfactant (i.e., rhamnolipid). Analyses with 13C NMR and mass spectrometry show that the biosurfactant consisted mainly of mono-rhamnolipid (RL1) and di-rhamnolipid (RL2). Since RL2 possesses higher surface activity than RLl and is of better applicability and commercial benefits, the present work attempted to enhance the production of RL2 over RL1 in P. aeruginosa J16 from the perspective of medium improvement. The results show that the abundance and composition of RL1 and RL2 varied with the type of carbon and nitrogen sources used. When glycerol and NH4Cl were used as the carbon and nitrogen sources, respectively, an RL2 production of 448.3 mg/L was obtained with a volumetric productivity of 4.67 mg/(L h) and a RL2/RL1 ratio of 4.22 (by mass). Replacing NH4Cl by (NH4)2SO4, the RL2 concentration and volumetric productivity were improved to 2121 mg/L and 22.1 mg/(L h), respectively, with the RL2/RL1 ratio of 3.0. To further enhance RL2 production, statistical experimental design methodology was applied to optimize the culture medium composition favoring RL2 synthesis. Three key parameters (glycerol, (NH4)2SO4, and MgSO4·7H2O) were selected by two-level factorial design. Response surface methodology was then used to identify the optimal composition of the three key parameters, giving an optimal concentration of 0.38 M, 33.3 mM, and 577 μM for glycerol, (NH4)2SO4, and MgSO4·7H2O, respectively. With this optimal medium, the RL2 production could be markedly elevated to a maximum concentration of 3190 mg/L and a volumetric productivity of 44.3 mg/(L h), while the RL2/RL1 ratio maintained nearly constant at a value of 3.0.

Keywords
Biosurfactant; Di-rhamnolipid; Pseudomonas aeruginosa; Statistical experimental design
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Enhanced di-rhamnolipid production with an indigenous isolate Pseudomonas aeruginosa J16
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 43, Issue 7, July 2008, Pages 769–774
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us