Exponential Fed-Batch Cultures of Klebsiella pneumoniae under Anaerobiosis Using Raw Glycerol as a Substrate to Obtain Value-Added Bioproducts

Abstract

In this study, Klebsiella pneumoniae BLh-1 was grown under exponential fed-batch mode in cultures using raw glycerol from biodiesel synthesis under anaerobiosis to produce value-added products. Specific growth rates of 0.035, 0.07, and 0.105 h -1 were tested and 1,3-propanediol (1,3-PDO) and ethanol were produced in all cultures, whereas the formation of 2,3-butanediol was not observed. The highest concentrations of 1,3-PDO (38.5 g L -1 ) and ethanol (13.2 g L -1 ) were achieved under the specific growth rate of 0.105 h -1 . Acetic and lactic acids were also produced at high concentrations (17.3 and 7.8 g L -1 , respectively) under these conditions. The yields of 1,3-PDO and ethanol increased over time, reaching final values of 0.56 and 0.19 g g -1 , respectively. Overall productivities were 1.43 g L -1 h -1 for 1,3-PDO and 0.49 g L -1 h -1 for ethanol. Compared to batch results, fed-batch operation favored K. pneumoniae metabolism towards the production of 1,3-PDO and ethanol, being an interesting process to add value to the ever-growing availability of raw glycerol from biodiesel industry.