Figure 2

Relation between intracellular LDH activity and gene copy number (A) or lactic acid conversion yields (B). The gene copy number was determined with fresh 24 h cultures. Activities are expressed in U per mg of total proteins, where 1 U is the amount of μmole NADH, H⁺ reduced by intracellular extract per min. For intracellular LDH activity, measurements were carried out in triplicate at 72 h of culture; error bars show the standard deviation. Conversion yields were measured during the screening assays at 138 h incubation.