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Optimization of culture medium for anaerobic production of rhamnolipid by recombinant P seudomonas stutzeri R hl for microbial enhanced oil recovery
Author(s) -
Zhao F.,
Mandlaa M.,
Hao J.,
Liang X.,
Shi R.,
Han S.,
Zhang Y.
Publication year - 2014
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.12269
Subject(s) - rhamnolipid , pseudomonas stutzeri , glycerol , yeast extract , microbial enhanced oil recovery , food science , chemistry , microbial consortium , bioreactor , fermentation , biology , biochemistry , bacteria , microorganism , pseudomonas aeruginosa , organic chemistry , genetics
Abstract Response surface methodology was employed to enhance the anaerobic production of rhamnolipid by recombinant P seudomonas stutzeri Rhl. Glycerol is a promising carbon source used to anaerobically produce rhamnolipid. In a Plackett–Burman design, glycerol, KH 2 PO 4 and yeast extract were significant factors. The proposed optimized medium contained the following: 46·55 g l −1 glycerol; 3 g l −1 NaNO 3 ; 5·25 g l −1 K 2 HPO 4 ·3H 2 O; 5·71 g l −1 KH 2 PO 4 ; 0·40 g l −1 MgSO 4 ·7H 2 O; 0·13 g l −1 CaCl 2 ; 1·0 g l −1 KCl; 1·0 g l −1 NaCl; and 2·69 g l −1 yeast extract. Using this optimized medium, we obtained an anaerobic yield of rhamnolipid of 3·12 ± 0·11 g l −1 with a 0·85‐fold increase. Core flooding test results also revealed that Ps. stutzeri Rhl grown in an optimized medium enhanced the oil recovery efficiency by 15·7%, which was 6·6% higher than in the initial medium. Results suggested that the optimized medium is a promising nutrient source that could effectively mobilize oil by enhancing the in situ production of rhamnolipid. Significance and Impact of the Study The ex situ application of rhamnolipid for microbial enhanced oil recovery (MEOR) is costly and complex in terms of rhamnolipid production, purification and transportation. Compared with ex situ applications, the in situ production of rhamnolipid in anaerobic oil reservoir is more advantageous for MEOR. This study is the first to report the anaerobic production optimization of rhamnolipid. Results showed that the optimized medium enhanced not only the anaerobic production of rhamnolipid but also crude oil recovery.