Production of Polyhydroxyalkanoates with High 3-Hydroxydodecanoate Monomer Content by fadB and fadA Knockout Mutant of Pseudomonas putida KT2442
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- 作者：Shao-Ping Ouyang ; Rong Cong Luo ; Si-Si Chen ; Qian Liu ; Ahleum Chung ; Qiong Wu ; Guo-Qiang Chen
- 刊名：Biomacromolecules
- 出版年：2007
- 出版时间：August 2007
- 年：2007
- 卷：8
- 期：8
- 页码：2504 - 2511
- 全文大小：204K
- 年卷期：v.8,no.8(August 2007)
- ISSN：1526-4602
文摘
Pseudomonas putida KT2442 produces medium-chain-length (MCL) polyhydroxyalkanoates (PHA) consistingof 3-hydroxyhexanoate (HHx), 3-hydroxyoctanoate (HO), 3-hydroxydecanoate (HD), and 3-hydroxydodecanoate(HDD) from a wide-range of carbon sources. In this study, fadA and fadB genes encoding 3-ketoacyl-CoA thiolaseand 3-hydroxyacyl-CoA dehydrogenase in P. putida KT2442 were knocked out to weaken the 
ta2.gif" BORDER=0 ALIGN="middle">-oxidation pathway.Two-step culture was proven as the optimal method for PHA production in the mutant termed P. putida KTOY06.In a shake-flask culture, when dodecanoate was used as a carbon source, P. putida KTOY06 accumulated 84 wt% PHA, much higher than 50 wt % PHA in its wild type KT2442. The PHA monomer composition was completelydifferent: the HDD fraction in PHA produced by KTOY06 was 41 mol %, much higher compared with 7.5 mol% only in KT2442. The fermentor-scale culture indicated the HDD fraction in PHA decreased during the culturetime from 35 to 25 mol % in a one-step fermentation process or from 75 to 49 mol % in a two-step fermentationprocess. It is for the first time that PHA with a dominant HDD fraction was produced. Thermal and mechanicalproperties assays indicated that this new type PHA with a high HDD fraction had higher crystallinity and tensilestrength than PHA with a low HDD fraction did, demonstrating an improved application property.
ta2.gif" BORDER=0 ALIGN="middle">-oxidation pathway.Two-step culture was proven as the optimal method for PHA production in the mutant termed P. putida KTOY06.In a shake-flask culture, when dodecanoate was used as a carbon source, P. putida KTOY06 accumulated 84 wt% PHA, much higher than 50 wt % PHA in its wild type KT2442. The PHA monomer composition was completelydifferent: the HDD fraction in PHA produced by KTOY06 was 41 mol %, much higher compared with 7.5 mol% only in KT2442. The fermentor-scale culture indicated the HDD fraction in PHA decreased during the culturetime from 35 to 25 mol % in a one-step fermentation process or from 75 to 49 mol % in a two-step fermentationprocess. It is for the first time that PHA with a dominant HDD fraction was produced. Thermal and mechanicalproperties assays indicated that this new type PHA with a high HDD fraction had higher crystallinity and tensilestrength than PHA with a low HDD fraction did, demonstrating an improved application property.