Sunday, August 12, 2012
Columbia Hall, Terrace Level (Washington Hilton)
The specialty chemical 3-hydroxypropionaldehyde is industrially important and is used in the production of plastics. A mutant strain of Citrobacter freundii ATCC 8090 capable of elevated 3-hydroxypropionaldehyde production from glycerol has been isolated using chemical mutagenesis and a screening process involving staining colonies on solid minimal medium containing 5% glycerol with a solution of 1% phloroglucinol. The mutant strain was grown in a complex medium containing soy biodiesel-based raw glycerol (ranging from 0.5% to 10%) for 24 hours at 28oC. The cells were collected by centrifugation and resuspended in a neutral phosphate buffer containing the same concentration of raw glycerol and 0.75% semicarbazide hydrochloride. After the cell suspensions were shaken for 24 hours at 28oC, the cells were collected by centrifugation. The resultant supernatant of each suspension was spectrophotometrically assayed for 3-hydroxypropionaldehyde. It was found that the highest level of 3-hydroxypropionaldehyde concentration was produced by the mutant strain at a concentration of 1.5% raw glycerol. When higher raw glycerol concentrations were utilized, the mutant strain failed to produce increased levels of 3-hydroxypropionaldehyde. In conclusion, it was found that the mutant strain produced its highest aldehyde concentrations at lower levels of soy biodiesel-based raw glycerol.