Racemization in Reverse: Evidence that D-Amino Acid Toxicity on Earth Is Controlled by Bacteria with Racemases

• DOI: 10.1371/journal.pone.0092101
• Publication Date: 2014-03-20T02:53:41Z
• Authors: Gaosen Zhang; Henry J. Sun
• Keywords: Racemization

D-amino acids are toxic for life on Earth. Yet, they form constantly due to geochemical racemization and bacterial growth (the cell walls of which contain acids), raising the fundamental question how ultimately recycled. This study provides evidence that bacteria use as a source nitrogen by running enzymatic in reverse. Consequently, when soils inundated with racemic amino acids, resident consume D- well L-enantiomers, either simultaneously or sequentially depending level their racemase activity. Bacteria thus protect Earth keeping environments acid free.