title: In situ dark field microscopy for on-line monitoring of yeast cultures.
abstract: A new-type in situ probe has been developed to acquire dark field images of yeast in bioreactors. It has been derived from an in situ bright field microscope that is able to measure cell density in bioreactors during fermentation processes. The illumination part of the probe has been replaced with a dark field device, in which an aspheric condenser is used, so that high contrast dark field images can be obtained. The technique of second imaging is implemented to improve the sharpness of the images by means of a relay lens. This new in situ probe is expected to enable the evaluation of the cell viability without staining owing to modern image processing.
authors.affiliation: Bielefeld University, Faculty of Technology, Fermentation Engineering, Bielefeld, Germany.
authors.forename: Ning
authors.initials: N
authors.lastname: Wei
authors.forename: Jia
authors.initials: J
authors.lastname: You
authors.forename: Karl
authors.initials: K
authors.lastname: Friehs
authors.forename: Erwin
authors.initials: E
authors.lastname: Flaschel
authors.forename: Tim Wilhelm
authors.initials: TW
authors.lastname: Nattkemper
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D002452:Cell Count / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008853:Microscopy / Q000295:instrumentation* / Q000379:methods; D009862:Online Systems; D015003:Yeasts / Q000166:cytology*