Quillaguamán Jorge, Doan-Van Thuoc, Guzmán Héctor, Guzmán Daniel, Martín Javier, Everest Akaraonye, Hatti-Kaul Rajni
Department of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00, Lund, Sweden.
Appl Microbiol Biotechnol. 2008 Feb;78(2):227-32. doi: 10.1007/s00253-007-1297-x. Epub 2007 Dec 21.
High poly(3-hydroxybutyrate) (PHB) content and volumetric productivity were achieved by fed-batch culture of Halomonas boliviensis using a defined medium. Initial shake flask cultivations in a minimal medium revealed that the growth of H. boliviensis was supported only when the medium was supplemented with aspartic acid, glycine, or glutamine. Addition of 0.1% (w/v) glutamine in the medium resulted in the highest cell dry weight (CDW; 3.9 g l(-1)). Glutamine was replaced by the less expensive monosodium glutamate (MSG) in the medium without any notable change in the final cell density. Effect of initial concentrations of NH(4)Cl and K(2)HPO(4) on cell growth and PHB accumulation by H. boliviensis was then analyzed using a fed-batch fermentation system. The best conditions for PHB production by H. boliviensis were attained using 0.4% (w/v) NH(4)Cl and 0.22% (w/v) K(2)HPO(4) and adding MSG intermittently to the fermentor. Poly(3-hydroxybutyrate) content and CDW reached 90 wt.% and 23 g l(-1), respectively, after 18 h of cultivation. In order to increase CDW and PHB content, MSG, NH(4)Cl, and K(2)HPO(4) were initially fed to the fermentor to maintain their concentrations at 2%, 0.4%, and 0.22% (w/v), respectively, and subsequently their feed was suppressed. This resulted in a CDW of 44 g l(-1), PHB content of 81 wt.%, and PHB volumetric productivity of 1.1 g l(-1) h(-1).
通过使用限定培养基对玻利维亚盐单胞菌进行补料分批培养，实现了高聚（3-羟基丁酸酯）（PHB）含量和体积产率。在基本培养基中进行的初始摇瓶培养表明，只有在培养基中添加天冬氨酸、甘氨酸或谷氨酰胺时，玻利维亚盐单胞菌才能生长。在培养基中添加0.1%（w/v）的谷氨酰胺可获得最高细胞干重（CDW；3.9 g l(-1)）。在培养基中用价格较低的味精（MSG）替代谷氨酰胺，最终细胞密度没有明显变化。然后使用补料分批发酵系统分析了初始氯化铵和磷酸氢二钾浓度对玻利维亚盐单胞菌细胞生长和PHB积累的影响。使用0.4%（w/v）氯化铵和0.22%（w/v）磷酸氢二钾，并向发酵罐中间歇添加味精，可获得玻利维亚盐单胞菌生产PHB的最佳条件。培养18小时后，聚（3-羟基丁酸酯）含量和CDW分别达到90 wt.%和23 g l(-1)。为了提高CDW和PHB含量，最初将味精、氯化铵和磷酸氢二钾加入发酵罐，使其浓度分别保持在2%、0.4%和0.22%（w/v），随后停止添加。这使得CDW达到44 g l(-1)，PHB含量达到81 wt.%，PHB体积产率达到1.1 g l(-1) h(-1)。
