Cornelius Bernardus Van Niel (November 4, 1897 - March 10, 1985) was an Dutch-America microbiologist. He introduced the study of general microbiology to the United States and made key discoveries explaining the chemistry of photosynthesis.
By studing purple and green bacteria he was the first scientist to demonstrate that photosynthesis is a light-dependent reaction redox reaction, in which hydrogen from an oxidizable compound reduces carbon dioxide to cellular materials. Expressed as:
- 2 H2A + CO2 --- >2A + CH2O + H2O
His discovery predicted that H2O is the hydrogen donor in green plant photosynthesis and is oxidized to O2. The chemical summation of photosyntheis was a milestone in the understanding of the chemistry of photosynthesis. This was later shown to be the case by Robin Hill.