Zymomonas mobilis cell viability: measurement method comparison.

Comparison of three different cell viability methods: slide count, plate count and methylene blue staining techniques, applied on Zymomonas mobilis cultures, was performed. The slide technique proved to be faster and more accurate than the plate count method, and both of them far more reliable than the standard methylene blue method which constantly overestimated the Zymomonas cell viability. The slide technique is advantageous also because it gives information on the cell morphology changes, notably the abnormal cell elongation, in the ethanol fermentation.