| Popis: |
Waste frying oil is gaining traction as a useful commodity, rather than a waste, especially for the production of biofuels, such as biodiesel. Transesterification of waste frying oil to biodiesel using alkali as a catalyst with addition of different solvents (such as methanol) also yields glycerol as a byproduct. Glycerol bioconversion into several valuable products is favored because it is relatively inexpensive, easily available, and also due to the possible utilization of different microorganisms. Bioethanol, glycerin soap, several organic acids, and chemical compounds are some of the examples of converted products using glycerol as substrate. In this chapter, bioethanol production by locally isolated bacterial strains and the comparison of the ethanol fermentation profile using glycerol as a sole carbon source are reported. Besides ethanol, production of several chemical compounds and organic acids are also possible. In total, nine isolated bacterial strains were tested for their ability to utilize glycerol and produce bioethanol. These isolates include Escherichia coli, Serratia marcescens, Aeromonas veronii, Shewanella putrefaciens, Acinetobacter johnsonii, Pseudomonas putida, Enterobacter kobei, Klebsiella pneumoniae, and Chryseobacterium gleum. Different parameters were evaluated and optimized for each strain, to screen the most potent strain that has the ability to utilize glycerol to produce ethanol. We observed that bacterial isolates produced ~0.12–0.25% ethanol, using biodiesel glycerol, within 24 hours. Although the yield was comparatively lower as compared to other reports, it is still encouraging, and could possibly be employed in bioethanol production using better-suited microorganisms. |
