The present invention includes compositions and methods for making and using halophilic cyanobacterium comprising a spontaneous mutation causing constitutive cellulose biosynthesis, whereby the cyanobacterium is capable of producing cellulose in brine. The compositions and methods of the present invention may be used as a new global crop for the manufacture of cellulose, CO.sub.2 fixation, for the production of alternative sources of conventional cellulose as well as a biofuel and precursors thereof.
STATEMENT OF FEDERALLY FUNDED RESEARCH
 This invention was made with U.S. Government support under Contract No. DE-FG02-03R15396 awarded by the Department of Energy. The government has certain rights in this invention.