  Environmental D-amino acids are thought to be derived from organic diagenesis such as racemization and release from bacterial cell walls and even from microbial production.
<fluency>   Environmental D-amino acids are thought to be derived from organic diagenesis such as racemization and release from bacterial cell walls and even from microbial production.
 " Environmental D-amino acids are thought to be derived from organic diagenesis such as racemization and release from bacterial cell walls and even from microbial production.