11-22: Comparison of 3-hydroxypropionaldehyde production by related enteric species on soy-based glycerol

Soy biodiesel production results in a coproduct stream of glycerol, fatty acids and methylesters of fatty acids. During biodiesel production, raw glycerol is the major coproduct. This low value glycerol can be used to ferment the specialty chemical 3-hydroxypropionaldehyde. The applications of 3-hydroxypropionaldehyde include its use in plastic production, as a food preservative and as a tissue fixative. In this study, the abilities of the enteric bacteria Klebsiella pneumoniae ATCC 211 and Klebsiella oxytoca ATCC 43165 to convert different concentrations of soy-based raw glycerol to 3-hydroxypropionaldehyde were compared. Both species were grown for 24 hours at 28^oC on a complex medium containing diluted raw glycerol. Once the cells were collected by centrifugation, they were resuspended in a neutral phosphate buffer containing diluted raw glycerol and semicarbazide hydrochloride. The cell suspension was shaken for 24 hours at 28^oC and the cells were collected by centrifugation. The supernatant of each suspension was colorimetrically assayed for 3-hydroxypropionaldehyde. Cells of K. pneumoniae ATCC 211 produced about 1.5-fold the concentration of 3-hydroxypropionaldehyde on 10% raw glycerol than on 5% raw glycerol. Cells of K. oxytoca ATCC 43165 produced only slightly more 3-hydroxypropionaldehyde on 5% raw glycerol than on 10% raw glycerol. The level of 3-hydroxypropionaldehyde produced by K. pneumoniae ATCC 211 on 5% or 10% raw glycerol was 18-fold or 22-fold, respectively, than the level produced by K. oxytoca ATCC 43165. Overall, it was found that the ability of Klebsiella to produce the specialty chemical 3-hydroxypropionaldehyde from raw glycerol depended upon which species was used.