Culture Condition

Alongside the medium's chemical composition, four physical parameters of the incubation environment must each be held within a narrow optimum range for a culture to grow well. The pH of the medium is normally adjusted to between 5.6 and 6.0 for best results - a medium that is too acidic or too alkaline interferes with nutrient uptake and gelling. Cultures are incubated at a constant temperature of 25 degC +/- 2 degC for optimal growth; temperatures much outside this range slow growth or trigger stress responses. Humidity and light intensity are also controlled together: cultures need 50-60% relative humidity and about 16 hours of photoperiod under cool white fluorescent tubes delivering roughly 1000 lux of illumination. Finally, aeration matters especially for liquid cultures - it is provided either by shaking the flasks or tubes on an aut …