乙酸积累对基因工程菌培养的影响及与培养基pH的关系

在rIL-2工程菌K_(802)(pLY—4)高密度培养中,发现培养液中有大量代谢副产物乙酸积累,乙酸的存在对工程菌的生长和产物的表达均有明显的抑制作用,这种抑制作用是制约工程菌高密度培养的重要因素。为了减小这种抑制作用,初步研究了培养基pH与乙酸抑制作用的关系,发现适当提高培养基pH值,能减小乙酸的抑制作用;高密度培养时,提高培养基的pH后,虽然仍有大量乙酸积累,但产物的表达水平和菌密度都有提高。

THE RESPONSITY OF RECOMBINANT ESCHERICHIA COLI GROWTH AND PRODUCTION ON THE ACETIC ACID ACCUMULATION IN CULTURE MEDIA

Fermentation studies were performed on an Escherichia coli culture that carries a recombinant plasmid composed of an ampicillin-resistante gene, a temperature-regulated PLPR promoter, and an interleukin-2 (IL-2) gene. The objective was to find the way to decrease the inhibition of acetic acid which was found accumulating in the media in high-cell-density culture. The responsity of the inhibition on the media pH was studied. Theresults suggested the inhibition could be decreased by regulation the media pH appropriately. In high-cell-density culture, the specific expression level and cell density was increased by raise the media pH, although there was much acetic acid accumulation too.