Journal of Chemical Technology and Biotechnology, Vol.78, No.2-3, 283-286, 2003
Genetic strategy for solving chemical engineering problems in biochemical engineering
Genetic manipulation can be used to solve some traditional chemical engineering problems in biochemical engineering such as in poly(beta-hydroxybutyrate) (PHB) production. To reduce the high production costs of PHB resulting from expensive raw materials, low productivity of the process and complexity of recovery steps, PHB biosynthetic genes (phbCAB), Vitreoscilla globin gene (vgb) and lytic genes of phage lambda with an S amber mutation (S(-)RRz) were simultaneously introduced into the same recombinant Escherichia coli, VG1 (pTU14). This will have the advantages of using phbCAB with cheap raw materials and accumulating a high content of PHB, with the ability of vgb to enable a higher specific oxygen uptake rate by the cells, and the characteristics of S(-)RRz to realize controllable cell lysis. In the fermentation of VG1 (pTU14), starch hydrolysate was used in place of glucose as a cheaper carbon source, and a PHB concentration and productivity as high as 167.6 g dm(-3) and 3.05 g dm(-3) h(-1) were easily realized at almost zero levels of dissolved oxygen (DO), and with a simple temperature-inducing treatment for recovery PHB with a purity of at least 95% was easily harvested. (C) 2003 Society of Chemical Industry.
Keywords:genetic strategy;PHB biosynthetic genes (phbCAB);Vitreoscilla haemoglobin gene (vgb);lytic genes of phage lambda with an S amber mutation (S(-)RRz)