a method is disclosed for producing 3 - hydroxypropionaldehyde from glycerol by culturing the bacterium klebsiella pneumoniae having the identifying characteristics of nrrl b - 4011 , under aerobic conditions , in an aqueous nutrient medium containing glycerol and a compound that causes 3 - hpa to be accumulated by blocking the conversion of 3 - hpa to trimethylene glycol . this process is particularly useful for the production , from renewable resources , of acrylic acid , an industrially important plymerizable monomer used in the manufacture of synthetic polymers and plastics and which is presently derived from fossil fuel sources .