Fig. 4

Bench-top fermentation of butyl acetate production. A Schematics for the fed-batch bioreactor fermentation with in situ product removal with gas striping setup. During the production phase, the bioreactor was connected to N₂ gas cylinder to maintain the anaerobic condition. The gas outlet of the fermenter was connected to three water trap in series to capture the evaporated butyl acetate. The first water trap is placed under room temperature as indicated by RT. The second and third trap, Cold trap 1 and 2, were placed under ice bath. The Graham condenser was connected to a refrigerated chiller with circulating water at 4 °C. B Alcohols and ester production, C cellular growth, and D byproduct secretion profile of strain YA5 during the fermentation. E Butyl acetate distribution and F butyl acetate to butanol ratio in fermentation broth, trap (room temperature) and 2 cold traps. The time point zero indicates the time switching culture into anaerobic condition by pumping nitrogen gas