Figure 5

Repetitive batch reaction by R. eutropha transformant H16-KLB4 with a jar fermenter. The vertical dotted lines represent the beginning of a new batch reaction. The reaction started with 120 ml of reaction mixture containing 110 ml cell suspension (1 g wet cell/5 ml reaction buffer) and 2% (v/v) hydroxyacetone. Hydroxyacetone was additionally supplied to the reaction mixture as the reaction proceeded in each batch reaction. Cells were harvested by centrifugation after 22–23 hr reaction, and were re-suspended in reaction buffer to make 120 ml of reaction mixture for the next batch reaction. The average reaction velocity of the respective batch reaction is shown in the figure. Cell harvest and re-suspension procedures were conducted anaerobically using a vinyl anaerobic chamber (Coy Laboratory Products Inc., MI, USA) (A) or were done aerobically under air (B). The SF prepared from the cell suspension used for the reaction contained 1.38 U/ml and 1.76 U/ml (A) and 1.75 U/ml and 1.62 U/ml (B) of ReSH and KlADH activities, respectively.