Rebeiz, C: Chlorophyll Biosynthesis/Technol. Applications

Heme and chlorophyll (Chl) are porphyrins. Porphyrins (also referred to as tetrapyrroles) are essential for life in the biosphere. Chlorophyll catalyzes the conversion of solar energy to chemical energy via the process of photosynthesis. Organic life in the biosphere is made possible by consumption of the chemical energy generated by photosynthesis.
Hemes are the prosthetic groups of cytochromes which are involved in electron transport during oxidative phosphorylation and photosynthetic phosphorylation which generate ATP and NADPH. The latter are essential for many cellular functions.
Chlorophyll on the other hands catalyzes the process of photosynthesis. Indeed, life in the biosphere depends on the process of photosynthesis which converts light energy, carbon dioxide and water into the chemical energy, required for the formation of food and fiber. Photosynthetic efficiency is controlled by extrinsic factors such as the availability of water, CO2, inorganic nutrients, ambient temperature and the metabolic and developmental state of the plant, as well as by intrinsic factors (Lien and San Pietro, 1975). The most important intrinsic factor is the efficiency of the photosynthetic electron transport system (PETS).
Conventional agriculture is one of the few human activities that have not undergone a revolution to join other activities such as overcoming gravity by flying, and landing on the moon, crossing underwater the polar cap, and communicating wirelessly over long distances via electromagnetic waves. We now feel that enough biochemical and molecular biological knowledge has accumulated to render this dream amenable to experimentation. We believe that the time has come to bioengineer chloroplasts capable of synthesizing a short chain carbohydrate such as glycerol at rates that approach the upper theoretical limits of photosynthesis [Rebeiz, C. A. (2010) Investigations of possible relationships between the chlorophyll biosynthetic pathway and the assembly of