The needs for sensors in bacterial and yeast fermentations--Sampling--On-line monitoring of bioprocesses using hplc--High-performance liquid chromatography--Applications of nadh-dependent fluorescence sensors for monitoring and controlling bioprocesses--Fiber-optic sensors in bioprocess control--Applications of electrochemical sensors--Electrochemical biosensors for bioprocess control--Thermistor probes--Flow injection analysis in bioprocess control--The use of on-line sensors in bioprocess control--Multicomponent analysis and chemometrics for bioprocess control