AUTHOR=Velmurugan Rajendran , Incharoensakdi Aran 

TITLE=Metal Oxide Mediated Extracellular NADPH Regeneration Improves Ethanol Production by Engineered Synechocystis sp. PCC 6803

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=7

YEAR=2019

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2019.00148

DOI=10.3389/fbioe.2019.00148

ISSN=2296-4185

ABSTRACT=<p>The ethanol synthesis pathway engineered <italic>Synechocystis</italic> sp. PCC 6803 (hereafter <italic>Synechocystis</italic>) was used to investigate the influence of metal oxide mediated extracellular NADPH regeneration on ethanol synthesis. The <italic>in-vitro</italic> studies proved that the metal oxides have the potential to generate the NADPH in the presence of electron donor, the usual components of photoautotrophic growth conditions. When the NADPH regeneration was applied in <italic>Synechocystsis</italic>, the strain showed improved growth and ethanol production. This improved ethanol synthesis is attributed to the increased availability of NADPH to the ethanol synthesis pathway and redirection of closely related carbon metabolism into the ethanol synthesis. Under optimized light intensity and NADP addition, the maximum ethanol production of 5,100 mg/L was observed in MgO mediated extracellular NADPH regeneration after 25 days of cultivation, which is 2-fold higher than the control. This study indicates the feasibility of metal oxide mediated extracellular NADPH regeneration of <italic>Synechocystis</italic> to increase the production of ethanol.</p>