van Neil, Cornelius B. (1897-1985)

Dutch microbiologist and teacher

Cornelius B. van Neil made pioneering contributions to the study of photosynthesis in the bacteria that are known as the purple and green sulfur bacteria. These rather exotic bacteria are plant-like in that they use specific wavelengths of sunlight as a source of energy, instead of the metabolism of carbon-containing compounds. In addition to his research contributions, van Neil is noteworthy because of his tremendous teaching contributions. He inspired many people to take up a career in research microbiology in the first half of the twentieth century. Several of his students went on to obtain the Nobel Prize for their scientific contributions.

Van Neil was born in Haarlem, The Netherlands. His interest in chemistry was sparked while he was still in high school. This interest led him to enroll in the Chemistry Division of the Technical University of The Netherlands. His education was interrupted by a brief stint in the Dutch army. But ultimately he received a degree in Chemical Engineering in 1923. He then became a laboratory assistant to Albert Jan Kluyver , a renowned microbial physiologist and taxonomist. van Neil was responsible for the culture collection of yeast , bacteria, and fungi that Kluyver has amassed. During this time, van Neil isolated Chromatium spp. and Thiosarcina rosea and demonstrated that their growth did not involve the production of oxygen.

van Neil received a Ph.D. from The Technical University in 1928 for his research on proprionic acid bacteria (now well-known as one of the causes of acne). Following this, he came to the United States to accept a position at the Hopkins Marine Station, a research institution of Stanford University located on the Monterey Peninsula. He remained at Hopkins until his retirement in 1962. From 1964 until 1968, he was a visiting Professor at the University of California at Santa Cruz. He then retired from teaching and research entirely.

During his tenure at the Hopkins Marine Station, van Neil produced his most fundamentally important work. He was able to demonstrate that the ability of purple and green sulfur bacteria to exist without oxygen depends on the presence of sunlight. The photosynthetic reaction causes carbon dioxide to become reduced, providing the building blocks needed by the bacteria for growth and division. van Neil went on to broaden his work to photosynthesis in general. His observations that radiant energy activates a hydrogen donating compound instead of carbon dioxide was seminal in the development of subsequent studies of photosynthetic reactions in nature.

Another area where van Neil made a fundamental contribution was the emerging field of bacterial classification. Through his efforts in identifying over 150 strains of bacteria, and consolidating these organisms into six species contained within the two genera of Rhodopseudomonas and Rhodo-spirillum, van Neil and Kluyver laid the groundwork for the use of bacterial physical and chemical characteristics as a means of classifying bacteria.

van Neil's teaching legacy is as important as his research contributions. He established the first course in general microbiology in the United States. He was a riveting lecturer, and his classes could last an entire day. He taught and mentored many students who went on to considerable achievements of their own.

See also Microbial taxonomy; Photosynthetic microorganisms