Expression of Shewanella oneidensis MR - 1 [ FeFe ] - hydrogenase 2 genes in Anabaena sp . strain PCC 7120

10 H2 generated from renewable resources holds promise as an environmentally innocuous fuel that 11 releases only energy and water when consumed. In biotechnology, photoautotrophic oxygenic 12 diazotrophs could produce H2 from water and sunlight using the cells’ endogenous nitrogenases. 13 However, nitrogenases have low turnover numbers and require large amounts of ATP. [FeFe]14 hydrogenases found in other organisms can have 1000-fold higher turnover numbers and no 15 specific requirement for ATP, but are very O2-sensitive. Certain filamentous cyanobacteria 16 protect nitrogenase from O2 by sequestering the enzyme within internally micro-oxic, 17 differentiated cells called heterocysts. We heterologously expressed the [FeFe]-hydrogenase 18 operon from Shewanella oneidensis MR-1 in Anabaena sp. strain PCC 7120 using the 19 heterocyst-specific promoter PhetN. Active [FeFe]-hydrogenase was detected in, and could be 20 Copyright © 2012, American Society for Microbiology. All Rights Reserved. Appl. Environ. Microbiol. doi:10.1128/AEM.01959-12 AEM Accepts, published online ahead of print on 28 September 2012 on Jne 4, 2017 by gest ht://aem .sm .rg/ D ow nladed fom