Use of Cell-Free Biological Systems for Hydrogen Production

摘要

Conceptual processes for the production of hydrogen from water using cell-free biological systems are analyzed. Proposed flowsheets include the chemical reduction of ferredoxin (the electron transport medium) or the photochemical reducing potential of illuminated chloroplasts for ferredoxin reduction, followed by the reaction of reduced ferredoxin with protons, catalyzed by hydrogenase, to produce hydrogen gas. Factors affecting hydrogen production rates are discussed. The optimum temperature for the ferredoxin-hydrogenase enzyme system is 40 to 45 exp 0 C. The rate of reduction of ferredoxin by dithionite was measured spectrophotometrically, and kinetic parameters were evaluated. The kinetics of ferredoxin oxidation by molecular oxygen is discussed, and possible methods for oxygen removal are considered. Various methods for enzyme immobilization were studied in terms of applicability to a continuous process for hydrogen production. (ERA citation 04:005390)