Technical Note 8 – OD600

Bacterial growth in liquid media is often tracked by measuring optical density at 600 nm (OD600). OD600 readings help determine a culture's growth stage, ensuring cells are harvested at the optimal point for live cell density. Bacterial cell growth typically passes through lag, log, stationary, and decline phases. Ideally, cells are harvested near the end of the log phase, using OD600 to identify this point. Cells are usually grown until OD600 reaches around 0.4 before induction or harvesting. OD600 results stem from light scattering, not absorption, and can vary between photometer types.

• Monitoring Bacterial Growth: Measuring Optical Density at 600 nm (OD600)
• Determining Growth Stage with OD600 Measurements
• Harvesting Cells at Optimal Density
• Bacterial Growth Phases: Lag, Log, Stationary, Decline
• Harvesting Cells Towards Log Phase End
• OD600 Absorbance Reaches Approximately 0.4 Before Induction/Harvesting
• Inconsistent OD600 Results Across Photometers
• NanoPhotometer Default Correction Factor: 1
• Recommended: 10 mm Path Length Disposable Cuvettes for Cell Culture OD Measurements