Patent ID: 11939559
Assignee: GENENTECH, INC.
Field: Biotechnology (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A method for culturing Chinese hamster ovary (CHO) cells comprising:
(i) providing a cell culture comprising from about 1.5×106 to about 10×106 CHO cells in about 20 L of a bicarbonate-containing culture liquid with a pH between 6.8 and 7.2 to a vessel, wherein said vessel has a volume of about 50 L and has walls that encapsulate said cell culture and a gas phase head space above said cell culture, and wherein said vessel comprises at least one port that provides an entrance and an egress of gas to and from said head space;
(ii) perfusing fresh culture medium into said vessel and removing spent culture medium from said vessel at a perfusion rate of about 1 volume per day; and
(iii) providing gas to said head space through said port to sweep accumulated CO2 from the head space of the vessel, wherein said gas is supplemented with O2 in an amount of 30% (v/v) of said gas 48 hours after the start of perfusion, thereby modulating pH of the cell culture to maintain the pH of the culture between pH 6.8 and 7.2, and maintaining dissolved O2 to a level greater than 20% of air saturation,
wherein the fresh culture medium has a pH of 7.2, clearance rate of the head space is between 0.002 and 0.1 head space volume per minute (hvm), the vessel is agitated by rocking the vessel at a rock rate between 19 and 25 rocks per minute (rpm) at a rock angle of between 8° and 12°, and wherein the method does not require continuous monitoring and feedback control of pH and dissolved O2.