초록
<P><B>Abstract</B></P> <P>Production of 3-hydroxypropionic acid (3-HP) or 1,3-propanediol (1,3-PDO) production from glycerol is challenging due to the problems associated with cofactor regeneration, coenzyme B<SUB>12</SUB> synthesis, and the instability of pathway enzymes. To address these complications, simultaneous production of 3-HP and 1,3-PDO, instead of individual production of each compound, was attempted. With over-expression of an aldehyde dehydrogenase, recombinant <I>Klebsiella pneumoniae</I> could co-produce 3-HP and 1,3-PDO successfully. However, the production level was unsatisfactory due to excessive accumulation of many by-products, especially acetate. To reduce acetate production, we attempted; (i) reduction of glycerol assimilation through the glycolytic pathway, (ii) increase of glycerol flow towards co-production, and (iii) variation of aeration rate. These efforts were partially beneficial in reducing acetate and improving co-production: 21g/L of 1,3-PDO and 43g/L of 3-HP were obtained. Excessive acetate (>150mM) was still produced at the end of bioreactor runs, and limited co-production efficiency.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>K. pneumoniae</I> was engineered for co-production of 3-HP and 1,3-PDO from glycerol. </LI> <LI> Co-production improved upon by-products reduction. </LI> <LI> The maximum 21g/L 1,3-PDO and 43g/L 3-HP were obtained in fed-batch bioreactor cultivation. </LI> <LI> Acetate accumulation was serious and limited further improvement of co-production. </LI> <LI> Activation of TCA cycle and ETC is suggested to reduce acetate and improve ATP supply. </LI> </UL> </P>