Fig. 5

Accumulation of intracellular NAD levels under a acetic acid conditions, and b low pH conditions. Total NAD comprises NADH and NAD⁺; NADH/NAD⁺ = NADH/(total NAD − NADH). Two repeats were performed for each strain, and error bars indicate standard deviation. The change of total NAD or NADH/NAD⁺ per microgram dry cell weight (DCW) between two time points indicated the accumulation of NAD or NADH/NAD⁺. DCW was calculated from OD _{600 nm} (1OD₆₀₀ = 0.323 gDCW/L). Asterisks above bars indicate t test significance between mutants and ZM4.*p = 0.0415; **p = 0.0384; ***p = 0.0326