Net production of N2O (white bars) and NH4+ (hatched bars) over a 5-day incubation period at 21 °C of S. loihica strain PV-4 batch cultures with 0.2 mM NO3− and 0.1, 0.2, 0.5, 1.0, 2.0 and 10.0 mM lactate. Each bar represents the average of triplicate samples, with error bars representing the s.d.