Fig. (2) Standard recipe for minimal medium, all cultures grown under the same conditions (37°C, 75 rpm). 20g Glucose, 0.5g sodium nitrate, 1g monobasic sodium phosphate, 1.2g sodium chloride, 0.05g zinc chloride, 15ml liquid minerals, 2ml Tween 80, 2ml copper complex solution, line drawn to guide the eye only.