The BioLector facilitates microbial and cell culture fermentations in screening and bioprocess development. The combination of the easy handling of microtiter plates, the high-throughput capacity and the powerful online-monitoring of all fermentation parameters makes it an inevitable screening technology. It provides non-invasive optical measurements of biomass- and protein concentrations as well as pH and DOT in up to 96 parallel micro bioreactors at a 1001,500 µL scale. The BioLector was successfully applied in clone screening, media and fermentation development.