Figure 1: Bioprocess fermentors are typically equipped with real-time monitoring devices such as temperature, pH, oxygen, or even viable cell density. The advantages of on-line over off-line measurements are easiness of use, timely results, and the possibility of immediate responses to the measured value. By contrast with the well-equipped fermentors used for production, the disposables used in bioprocess development have lacked such on-line measurement devices so far. Cultivation conditions could be monitored only by means of off-line sampling, typically performed…