3-Hydroxypropanal is a broad-spectrum antimicrobial substance termed reuterin produced by Lactobacillus reuteri. L. reuteri resides in the gastrointestinal tract of healthy humans and animals, and is believed to. function as a symbiont in the enteric ecosystem. Synthesis of such an antimicrobial substance by an enteric resident raises a number of interesting questions and possibilities as to the role these residents may play in the health of the host. In vivo, glycerol is converted in one enzymatic step into 3-Hydroxypropanal. The 3-Hydroxypropanal -producing Lactobacillus reuteri is used as a probiotic in the health care of humans and animals. 3-Hydroxypropanal forms, together with Hydroxypropanal-hydrate and Hydroxypropanal-dimer, a dynamic, multi-component system (Hydroxypropanal system) used in food preservation, as a precursor for many modern chemicals such as acrolein, acrylic acid, and 1, 3-propanediol (1, 3-PDO), and for polymer production. 3-Hydroxypropanal can be obtained both through traditional chemistry and bacterial fermentation. To date, 3-HPA has been produced from petrochemical resources as an intermediate in 1, 3-PDO production. The biotechnological production of 3-Hydroxypropanal from renewable resources is desirable both for use of 3-Hydroxypropanal in foods and for the production of bulk chemicals. The main challenge will be the efficient production and recovery of pure 3-Hydroxypropanal.(