Effect of By-products on Cell Growth and Biosynthesis of 1,3-Propanediol by Klebsiella pneumoniae

Biosynthesis of 1,3-propanediol attracted much attention recently.The cell growth and biosynthesis of 1,3-propanediol by Klebsiella pneumoniae tended to be ceased in the latter phase of anaerobic culture.The effect of environmental factors was studied in this work.It was indicated that the main by-product ethanol was the key inhibitor.Addition of 4 g/L ethanol in the culture medium would restrain the cell growth and 1,3-propanediol formation.By addition of 8 g/L ethanol,the maximum specific rates of cell growth and 1,3-propanediol biosynthesis,the maximum concentrations of biomass and 1,3-propanediol were decreased by 21.6%,22.1%,59.6% and 33.5% respectively.The inhibition potentials of other by-products on the anaerobic growth of K.pneumoniae were also detected.It was shown that the cell growth was inhibited obviously with 2 g/L acetic acid,yet it would not be affected even with 5 g/L 2,3-butanediol or 10 g/L lactic acid.