Table 2. Physiological characterization of N402 and ΔracA strains.

	N402	ΔracA
Maximum specific growth rate (h−1)	0.22±0.01	0.24±0.01
Yield (gdw gmaltose −1)	0.60±0.02	0.63±0.03
Respiratory quotient (RQ)	0.97±0.05	1.03±0.03
Acidification (mmolbase gdw −1 h−1)	1.19±0.06	1.17±0.02
Specific protein secretion rate (mgprotein gdw −1 h−1)	0.49±0.07	0.53±0.02

Biomass samples were taken from triplicate independent batch cultivations using maltose as carbon source (Fig. 2). Mean values ± standard deviations are given. No significant difference was observed with any of the variables (two tailed t-test, p<0.01). RQ, respiratory quotient calculated as the ratio of CO₂ production and O₂ consumption rates.