| abstract |
The present invention provides a process for periplasmic expression of bacterial toxoid, which process comprises the following steps: a) growing a gram negative host cell culture in a fermentation medium, the host cell being transformed with a polynucleotide, wherein the polynucleotide encodes bacterial toxoid and periplasmic signal sequences; Or providing a gram negative host cell, wherein the host cell is transformed with a polynucleotide, the polynucleotide encodes a bacterial toxoid and periplasmic signal sequence, and the gram negative host cell is expressed in the periplasm. Containing a bacterial toxoid a (i)) inducing the expression of bacterial toxoid; b) mature the host cell, the maturation steps are: I) subjecting host cells to pH shock; II) incubating the host cells without feed addition; and / or III) subjecting host cells to temperatures below -20 ° C, A step comprising: c) extracting bacterial toxoid from the host cell, wherein the extraction step comprises osmotic shock; Is included. [Selection figure] None |