초록
<P><I>Gluconobacter oxydans</I> is used to produce xylitol from <SMALL>d</SMALL>-arabitol. This study aims to improve xylitol production by increasing the coenzyme regeneration efficiency of the pentose phosphate pathway in <I>G. oxydans</I>. Glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were overexpressed in <I>G. oxydans</I>. Real-time PCR and enzyme activity assays revealed that G6PDH/6PGDH activity and coenzyme regeneration efficiency increased in the recombinant <I>G. oxydans</I> strains. Approximately 29.3 g/L xylitol was obtained, with a yield of 73.2%, from 40 g/L <SMALL>d</SMALL>-arabitol in the batch biotransformation with the <I>G. oxydans</I> PZ strain. Moreover, the xylitol productivity (0.62 g/L/h) was 3.26-fold of the wild type strain (0.19 g/L/h). In repetitive batch biotransformation, the <I>G. oxydans</I> PZ cells were used for five cycles without incurring a significant loss in productivity. These results indicate that the recombinant <I>G. oxydans</I> PZ strain is economically feasible for xylitol production in industrial bioconversion.</P><P><B>Graphic Abstract</B><BR><IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jafcau/2016/jafcau.2016.64.issue-5/acs.jafc.5b05509/production/images/medium/jf-2015-05509p_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jf5b05509'>ACS Electronic Supporting Info</A></P>