초록
<P><B>Highlights</B></P><P>► Fourteen genes encoding aldehyde dehydrogenases were cloned and expressed in <I>Klebsiella pneumoniae</I>. ► Expression of <I>Escherichia coli</I> <I>aldH</I> resulted in the highest 3-HP production under anaerobic condition. ► 24.4g/L of 3-HP were produced in 24h in anaerobic fed-batch culture in a 5-L reactor. ► Carbon and redox balances were performed.</P> <P><B>Abstract</B></P><P>In this study, an aldehyde dehydrogenase (ALDH) was over-expressed in <I>Klebsiella pneumoniae</I> for simultaneous production of 3-hydroxypropionic acid (3-HP) and 1,3-propanediol (1,3-PDO). Various genes encoding ALDH were cloned and expressed in <I>K. pneumoniae</I>, and expression of <I>Escherichia coli</I> <I>aldH</I> resulted in the highest 3-HP titer in anaerobic cultures in shake flasks. Anaerobic fed-batch culture of this recombinant strain was further performed in a 5-L reactor. The 3-HP concentration and yield reached 24.4g/L and 0.18mol/mol glycerol, respectively, and at the same time 1,3-PDO achieved 49.3g/L with a yield of 0.43mol/mol in 24h. The overall yield of 3-HP plus 1,3-PDO was 0.61mol/mol. Over-expression of the <I>E. coli</I> AldH also reduced the yields of by-products except for lactate. This study demonstrated the possibility of simultaneous production of 3-HP and 1,3-PDO by <I>K. pneumoniae</I> under anaerobic conditions without supply of vitamin B<SUB>12</SUB>.</P>