The invention relates to a method for operating a
biological process plant (1) for producing biological products, in which the
biological process plant (1) comprises a source container (2) for
cell culture, a harvest container (3) for biological production and a clarification arrangement (4) with a
centrifuge (12), in which the source container (2) is operated in a circulating production mode, the circulating production mode comprises the following steps: a) initiating the circulating production mode in the source container (2), b) culturing the cells in the source container (2), thereby obtaining a
cell culture fluid (7) comprising the cultured cells, c) discharging a
discharge portion (16) of the
cell culture fluid (7) from the source container (2), d) combining a restart portion (17) of the
cell culture fluid (7) with a fresh culture medium (8) and repeating step b), e) repeating steps c) and d) at least once, and / or f) discharging the
cell culture fluid (7) obtained from step d) from the source container (2) in which the cyclic production mode is stopped, obtaining a discharged portion (16), wherein the method further comprises the steps of i) centrifuging the
discharge portion (16) via the
centrifuge (12), thereby separating the
discharge portion (16) into at least a centrifuged discharge portion (19) and a supernatant (14) and, preferably, a
biological product, ii) operating the harvest container (3) in a production mode wherein steps i) and ii) are performed at least twice.