TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Components: The enzyme used in step (a) is selected from carbonic anydrase (CA), carbonic anydrase immobilized on chitosan beads, or single enzyme nanoparticle of CA (SEN CA) or their analogues. The concentration of enzyme is 1-5 mg/l of CO2 saturated water.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: In the process, formaldehyde is formed along with carbon monoxide (CO), where the yield of formaldehyde is 0.0004-0.345 parts per million (ppm). The photocatalyst used is recovered by filtration and is reused for several cycles with consistent activity. Preferred Components: The photocatalyst used in step (b) and (c) is selected from titania, zinc oxide, zinc in the presence of light, nanoferrite, n-doped mesotitania, perovskite, mixed oxides, supported titanium oxide (TiO2) and carbon nanoparticle. The concentration of titania varied from 1-65 mg/l of CO2 saturated water. The quantity of TiO2 used in the reaction is 0.01-10 mol.% of active species with respect to the substrate. The concentration of zinc oxide/zinc varied from 10-65 mg/l of CO2 saturated water. The quantity of zinc oxide used in the reaction is 0.01-10 mol.% of active species with respect to the substrate. The metal donor is selected from zinc, magnesium, copper, and aluminum. The co-catalyst is selected from platinum, zinc, nickel, copper, manganese, magnesium, iron and tin. The source of illumination is tungsten filament lamp.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The sacrificial donor is selected from ethanol and methanol. EXAMPLE - Pure HPLC water (10 ml) was placed in a vial. Carbon dioxide gas (CO2) was bubbled in the water, through a needle dipping in this water. The CO2 was flowed under a pressure of 2 bar for 60 minutes from a CO2 cylinder. During this operation, the solution was maintained under constant agitation at a speed of 600 revolutions per minute with a magnetic stirrer and the flask was open to the ambient air. When CO2 gas bubbling was stopped, the openings were immediately closed with an aluminum seal using a crimper. Two tests were carried out in parallel, one in which a total quantity of 1 mg of CA (Carbonic anhydrase) enzyme previously dissolved in the buffer (1 ml, 1M, pH=8.3) with zinc (65 mg) as electron donor another one without any enzyme but with zinc as electron donor. The sample was tested in photocatalytic reactor for hydrogen generation. The hydrogen produced was analyzed, where the hydrogen evolution rate was approximately (5.165 mu moles/h), 20.66 mu moles/4h/mg of protein in absence of illumination. The hydrogen evolution rate was (0.625 mu moles/h), 2.5 mu moles/4h/mg in absence of enzyme and illumination.