Abstract
The continuous demand for alternative biofuels resulted in a significant rise of biodiesel production in last decade. As a consequence, high quantities of raw glycerol have been accumulated. The conversion of this abundant carbon source into value-added products using biotechnology consists in a significant opportunity for industry. Crude glycerol may be used in different processes, including bioconversion to 1,3-propanediol (1,3-PDO). 1,3-PDO is an important intermediate chemical for polymer synthesis. Some species are known to produce 1,3-PDO by fermentation of glycerol as K. pneumoneae, E. agglomerans, C. freundii, C. acetobutylicum, C. butyricum, C. pasterianum, L. brevis and L. buchneri. In this work, the objective was to produce 1,3- PDO by Clostridium butyricum NCIMB 8082 cultivated on biodiesel derived glycerol using batch and fed-batch strategies. The experiments were performed in the 1.0 L reactor, under anaerobic conditions, at200 rpm with temperature (37°C) and pH (7,0) control. In batch and fed-batch fermentations, initial glycerol concentration was 60 g.L-1and 20 g.L-1,respectively. In fed-batch fermentation, two feeds were performed containing 20 g.L-1 each one. The glycerol consumption and product formation were analysed by high- performance liquid chromatography (HPLC). After approximately 13 hours of fermentation, a concentration of 32.18 g.L-1 of 1,3-PDO in batch condition was reached.. In fed-batch condition, the 1,3-PDO final concentration was 29.83 g.L-1 after 11 hours of fermentation. The productivity values were 2.38 and 2.55 g.L- 1.h-1 in batch and fed-batch conditions, respectively.
