Oxygen is essential for life. Measuring oxygen concentrations plays a central role in controlling biotechnological processes . No matter if fermentations, scale-up studies, bioproductions in lab or industrial scale, the BCP-O2 sensor determines the oxygen concentration in realtime (real time monitoring) in a very convenient way. By measuring the oxygen concentrations oxygen limitations can be avoided and conclusions to metabolic activity can be drawn. With the help of measuring the oxygen important process parameters as OTR oxygen transfer rate or respiratory quotient RQ can be determined. Using BCP-O2 simplifies process optimization in bioprocessing and makes it efficient and precise. In contrast to other sensors the BCP-O2 has in integrated automated temperature and pressure compensation and can be connected to each and every fermenter type. BCP-O2 doesn´t need a minimum flow rate and thus can be applied from small (lab) scale (e.g shake flask) up to the large industrial scale.