US application 20150125934: METHOD FOR SELECTIVELY CULTURING MICROORGANISM USING PHOSPHITE DEHYDROGENASE GENE AS MARKER
A method for selectively culturing a microorganism, the method comprising the step of culturing, in a culture medium containing phosphorous acid as a sole phosphorous source and containing no antibiotic substance, a recombinant microorganism into which a phosphite dehydrogenase gene has been introduced, the microorganism having introduced thereinto a plasmid containing the phosphite dehydrogenase gene, the method making it possible to, in a case where the microorganism is subcultured, stably maintain the number of copies of the plasmid.
Paragraph 110 notes
 Although not particularly limited, an NADP-utilizing phosphite dehydrogenase can be used as appropriate in the selective culturing method of the present invention. Photosynthetic organisms including cyanobacteria are known to generally have high intracellular NADP concentrations, as Calvin cycle is used. Meanwhile, heterotrophic bacteria such as E. coli generally have high intracellular NAD concentrations.