Thermophilic bacterium Caldimonas taiwanensis
- 作者：Der-Shyan Sheu ; Wen-Ming Chen ; Jr-Yung Yang ; Rey-Chang Chang
- 关键词：Polyhydroxyalkanoate ; Starch ; Thermophile
- 刊名：Enzyme and Microbial Technology
- 出版年：2009
- 期刊代码：26_01410229
- 类别：ce
- 出版时间：6 May 2009
- 卷：44
- 期：5
- 页码：289-294
- 文件大小：249 K
摘要
Caldimonas taiwanensis accumulated polyhydroxybutyrate (PHB) at 55 °C from gluconate, fructose, maltose, and glycerol under nitrogen-limited condition. The PHB content peaked at 14 h after inoculation from gluconate. C. taiwanensis did not grow or accumulate PHA from fatty acids as the sole carbon source; however, it incorporated 3-hydroxyvalerate (3-HV) into PHB polymer from gluconate and valerate as a mixed carbon source. By adjusting the valerate concentration, the molar fraction of 3-HV could be modulated from 10 mol%to 95 mol%. Fatty acid valerate substantially inhibited cell growth and PHA accumulation with the addition of as little as 5 mM to the medium. Supplementing the medium with yeast extract overcame the inhibition, which enhanced not only the yield of biomass but also PHA productivity. The in vivo substrate specificity of PHA synthase ranged from C4 to C6. In addition, C. taiwanensis also incorporated a wide range of 3-HV into PHA from soluble starch and valerate as a mixed carbon source. Food-grade starches made from cassava, corn, potato, sweet potato and wheat respectively mixed with valerate were studied for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] production. In this study, C. taiwanensis exhibited high promise for reducing the production cost of P(3HB-co-3HV).