Overview of methods for Κ

Overview of typical methods

The table offers a concise overview of the main methods used to determine Κ. Use the links below to explore detailed information.

Analytical method	Advantages	Disadvantages
BactoBox® for Κ	Fast and precise Easy to standardize Total cell concentration is constant after onset of stationary phase	Bacteria in clumps and chains may be underestimated Not suitable when bacterial concentrations are substantially lower than non-bacterial particle concentrations.
Fluorescence Flow Cytometry (FFC) for K	Fast and precise Versatile Total cell concentration is constant after onset of stationary phase	Staining requires optimization FFC instruments are expensive FFC requires skilled operators
Microscopy for K	Direct count technique (no proxy) Possible to count individual cells in chains and clumps Total cell concentration is constant after onset of stationary phase	Low throughput Manual counting is slow and operator-dependent Relatively low precision
Off-line optical methods Optical methods for Κ	Fast and simple Inexpensive	Calibration factors are required to convert arbitrary OD units to cell concentrations Calibration factors shift as cell size changes in different media and growth phases Does not distinguish between bacterial and non-bacterial objects
On-line optical methods Optical methods for Κ	High throughput in 96-well plate readers Frequent, automated measurements	OD saturates at higher concentrations Calibration factors shift as cell size changes in different media and growth phases 96-well plates do not mimic flask and bioreactor conditions Does not distinguish between bacterial and non-bacterial objects
Plate counts for Κ	Gold standard for viable cell counts Counts only cells. Non-bacterial background is excluded	Low throughput Slow (days) CFU concentrations reach their peak in a relatively short time span Relatively low precision
Dry cell weight for Κ	Quantitative and robust Gold standard for biomass determination	Low throughput Slow (hours) Calibration factors are required to convert weight to cell concentrations Calibration factors shift as cell size changes in different media and growth phases Does not distinguish between bacterial and non-bacterial objects