초록
<P><B>Abstract</B></P><P><B>Aims</B></P><P>To identify the native‐occurring adipate pathway in a previously engineered <I>Thermobifida fusca</I> B6 strain and optimize the adipic acid production of this strain on glucose and corncob.</P><P><B>Methods and Results</B></P><P>The native‐occurring adipate pathway in <I>T.？fusca</I> B6 was identified to be the reverse adipate degradation pathway, including five steps: <I>β</I>‐ketothiolase (Tfu_0875), 3‐hydroxyacyl‐CoA dehydrogenase (Tfu_2399), 3‐hydroxyadipyl‐CoA dehydrogenase (Tfu_0067), 5‐Carboxy‐2‐pentenoyl‐CoA reductase (Tfu_1647) and succinyl‐CoA synthetase (Tfu_2576, Tfu_2577). The cell lysates of <I>T.？fusca</I> wild‐type strain with the addition of the Tfu_1647 protein produced trace adipic acid, while no adipic acid was produced in the absence of this protein. The above results prove that the low expression of <I>Tfu_1647</I> in the wild‐type strain was the reason why it did not produce any adipic acid. We then demonstrated that in <I>T.？fusca</I> B6, the maximal titre of adipic acid on 50？g？l<SUP>−1</SUP> glucose was 2·23？g？l<SUP>−1</SUP> with 0·045？g？g<SUP>−1</SUP>‐glucose yield and 0·22？g？l<SUP>−1</SUP> adipic acid was produced from 19·38？g？l<SUP>−1</SUP> milled corncob.</P><P><B>Conclusions</B></P><P>The reverse adipate degradation pathway was found to be responsible for the adipate synthesis in <I>T.？fusca</I> B6 and Tfu_1647 was the regulatory node on this pathway.</P><P><B>Significance and Impact of the Study</B></P><P><I>Thermobifida fusca</I> B6 was the first reported micro‐organism using its native‐occurring pathway to accumulate adipic acid. It had the highest reported yield and titre of adipic acid so far.</P>