Kalaiyezhini D, Ramachandran K B
a Department of Biotechnology , Indian Institute of Technology: Madras , Chennai , India.
Prep Biochem Biotechnol. 2015;45(1):69-83. doi: 10.1080/10826068.2014.887582.
In this study, the kinetics of poly-3-hydroxybutyrate (PHB) biosynthesis from glycerol by Paracoccus denitrificans DSMZ 413 were explored in a batch bioreactor. Effects of inorganic and organic nitrogen source, carbon to nitrogen ratio, and other process variables such as pH, aeration, and initial glycerol concentration on PHB production were investigated in a 2.5-L bioreactor. Yeast extract was found to be the best nitrogen source compared to several organic nitrogen sources tested. At pH 6, specific growth rate, product formation rate, and accumulation of PHB within the cell were maximum. Specific growth rate increased with increase in oxygen transfer rate, but moderate oxygen transfer rate promoted PHB production. High glycerol concentration inhibited specific product formation rate but not growth. High initial carbon/nitrogen (C/N) ratio favored PHB accumulation and its productivity. At a C/N ratio of 21.4 (mol mol(-1)), 10.7 g L(-1) of PHB corresponding to 72% of cell dry weight was attained.
在本研究中，利用反硝化副球菌DSMZ 413在分批式生物反应器中探索了由甘油生物合成聚3-羟基丁酸酯（PHB）的动力学。在2.5升生物反应器中研究了无机和有机氮源、碳氮比以及其他工艺变量（如pH值、通气量和初始甘油浓度）对PHB产量的影响。与几种测试的有机氮源相比，酵母提取物被发现是最佳氮源。在pH值为6时，比生长速率、产物形成速率以及细胞内PHB的积累量均达到最大值。比生长速率随氧传递速率的增加而增加，但适度的氧传递速率促进了PHB的产生。高甘油浓度抑制了比产物形成速率，但不影响生长。高初始碳/氮（C/N）比有利于PHB的积累及其生产率。在C/N比为21.4（mol mol⁻¹）时，获得了10.7 g L⁻¹的PHB，相当于细胞干重的72%。
