초록
<P><B>Background</B></P><P>1,3-propanediol (PDO) is a substantially industrial metabolite used in the polymer industry. Although several natural PDO production hosts exist, e.g. <I>Klebsiella</I> sp., <I>Citrobacter</I> sp. and <I>Clostridium</I> sp., the PDO yield on glycerol is insufficient for an economically viable bio-process. Enhancing this yield via strain improvement can be achieved by disconnecting the production and growth pathways. In the case of PDO formation, this approach results in a microorganism metabolizing glycerol strictly for PDO production, while catabolizing a co-substrate for growth and maintenance. We applied this strategy to improve the PDO production with <I>Citrobacter werkmanii</I> DSM17579<I>.</I></P><P><B>Results</B></P><P>Genetic tools were developed and used to create <I>Citrobacter werkmanii</I> DSM17579 ∆<I>dhaD</I> in which <I>dhaD,</I> encoding for glycerol dehydrogenase, was deleted. Since this strain was unable to grow on glycerol anaerobically, both pathways were disconnected. The knock-out strain was perturbed with 13 different co-substrates for growth and maintenance. Glucose was the most promising, although a competition between NADH-consuming enzymes and 1,3-propanediol dehydrogenase emerged.</P><P><B>Conclusion</B></P><P>Due to the deletion of <I>dhaD</I> in <I>Citrobacter werkmanii</I> DSM17579, the PDO production and growth pathway were split. As a consequence, the PDO yield on glycerol was improved 1,5 times, strengthening the idea that <I>Citrobacter werkmanii</I> DSM17579 could become an industrially interesting host for PDO production.</P>