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Updated: May 13, 2026

Precise, High-throughput Analysis of Bacterial Growth
Published on: September 19, 2017
A cost-effective solution for the reliable determination of cell numbers of microorganisms in liquid culture
Jacob J Lamb1, Julian J Eaton-Rye, Martin F Hohmann-Marriott
1Department of Biochemistry, University of Otago, Dunedin, New Zealand. lamja264@student.otago.ac.nz
Abstract:
The concentration of microorganisms in growth medium is an important parameter in microbiological research. One of the approaches to determine this parameter is based on the physical interaction of small particles with light that results in light scattering. Table-top spectrophotometers can be used to determine the scattering properties of a sample as a change in light transmission. However, a portable, reliable, and maintenance-free instrument that can be built from inexpensive parts could provide new research opportunities. In this report, we show how to build such an instrument. This instrument consists of a low power monochromatic light-emitting diode, a monolithic photodiode, and a microcontroller. We demonstrate that this instrument facilitates the precise determination of cell concentrations for the bacteria Escherichia coli and Pseudomonas aeruginosa as well as the cyanobacterium Synechocystis sp. PCC 6803 and the green alga Chlamydomonas reinhardtii.
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