The Huck Institutes of the Life Sciences

Huck Institutes' faculty member overturns nearly half a century of erroneous science

Dr. Donald Bryant and his research team discover genes coding for complete TCA cycle in cyanobacteria

Many textbooks will need to be revised after Dr. Bryant and his team discovered a previously overlooked step in the tricarboxylic acid (TCA) cycle of cyanobacteria.

Since 1967, researchers have operated under the flawed conclusion that because cyanobacteria do not produce succinyl-coenzyme A they cannot complete the TCA cycle to produce ATP.

Bryant and his team, however, found that the cyanobacterium Synechococcus sp. PCC 700 has genes that code for succinic semialdehyde dehydrogenase and 2-oxo-glutarate decarboxylase, which together complete the TCA cycle through the production of an intermediate molecule, known as succinate.

The team went on to confirm the presence of the genes in all but a few marine species of cyanobacteria, and expressed their hope that these findings could be used to create a new cyanobacterium to synthesize 1,4-butanediol — the organic precursor for making biofuels and plastics.

The study has been published in Science.

About Dr. Bryant

Dr. Donald Bryant is the Ernest C. Pollard Professor of Biotechnology and a professor of biochemistry and molecular biology at Penn State, and is a faculty member of the Huck Institutes’ graduate program in plant biology.

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