NOVELTY - Photosynthetic production of butanol comprises growing a transgenic designer plant or plant cells in a liquid medium, where the plant or plant cells are genetically engineered to express a set of enzymes that act on an intermediate product of the Calvin cycle and convert the intermediate product into butanol; and recovering butanol from the liquid medium.    USE - The method, construct and plant are useful for photosynthetic production of butanol (claimed).    ADVANTAGE - The present invention provides a new photobiological butanol-producing mechanism with a high solar-to-butanol energy efficiency. It provides revolutionary designer photosynthetic organisms, which are capable of directly synthesizing butanol from CO2 and water using sunlight. The butanol production methods of the present invention completely eliminate the problem of recalcitrant lignocellulosics by bypassing the bottleneck problem of the biomass technology. The photobiological butanol-production technology is expected to have a much higher solar-to-butanol energy-conversion efficiency than the current technology and could also help protect the Earth's environment from the dangerous accumulation of CO2 in the atmosphere.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are:    (1) a nucleic acid construct comprising from 5'to 3', an inducible promoter, a nucleotide sequence coding for a stroma signal peptide, and a nucleotide sequence coding for a photosynthetic butanol-production-pathway enzyme or for at least one enzyme that facilitates the andPH/NADH conversion or starch degradation and glycolysis, or a nucleic acid construct comprising from 5'to 3', an inducible promoter, and a nucleotide sequence coding for an interfering RNA molecule that inhibits the expression of a starch-synthesis enzyme;    (2) a transgenic plant or plant cell useful for photosynthetic production of butanol, comprising a nucleic acid construct of (1), the plant is genetically engineered to inducibly express phosphoglycerate mutase, enolase, pyruvate kinase, pyruvate-ferredoxin oxidoreductase (or pyruvate-NADP oxidoreductase), thiolase, 3-hydroxybutyryl-coenzyme A (CoA) dehydrogenase, crotonase, butyryl-CoA dehydrogenase, butyraldehyde dehydrogenase, and butanol dehydrogenase in the chloroplast;    (3) a method for biosafety-guarded photosynthetic production of biofuel by growing a cell-division-controllable transgenic designer plant or plant cells in a liquid medium, where the plant or plant cells are genetically engineered to contain a designer biosafety mechanism and express a set of designer biofuel-production-pathway enzymes that act on an intermediate product of the Calvin cycle and convert the intermediate product into biofuel; and recovering biofuel from the liquid medium; and    (4) a process for photosynthetic production of biofuel by (i) growing a cell-division-controllable transgenic designer plant, alga, blue-green alga (oxyphotobacterium), or plant cell in a liquid medium comprising water, where the transgenic designer plant, alga, blue-green alga, or plant cell comprises at least one exogenous transgene for at least one designer biofuel-production pathway, (ii) inducing the transgenic designer plant, alga, blue-green alga, or plant cell to create induced transgenic organism having the at least one transgene activated to confer at least one designer biofuel-production pathway, and (iii) providing carbon dioxide and light energy, where the induced transgenic designer plant, alga, blue-green alga, or plant cell converts the carbon dioxide, water and light energy to certain intermediate products and finally to biofuel (such as ethanol and/or butanol) and oxygen.