Glycerol-Based Biorefinery for Fuels and Chemicals

Abstract

The rapidly expanding market for bioethanol and biodiesel is remarkably altering the cost and availability of glycerol. In general, approximately 10 pounds of crude glycerol are formed for every 100 pounds of biodiesel produced. Bioethanol process also generates glycerol up to 10% (w/w) of the total sugar consumed as a byproduct. Crude glycerol has thus been widely recognized as an attractive sustainable resource for chemical industries. Glycerol-based biorefinery is the microbial fermentation processes using inexpensive and readily available glycerol as the raw material to produce fuels and chemicals. A major challenge in fermentation of the low-grade crude glycerol is to obtain microbial strains tolerant to undesirable inhibitory components such as salts and organic solvents that present in crude glycerol. There have been several attempts to explore anaerobic microbial assimilation of glycerol using reconstructed microbial systems via microbial screening and metabolic pathway engineering. As a result, fuels as well as some high-value products were found to be produced by microbial fermentation of glycerol. This review describes biological processes using glycerol that produce fuels and chemicals including 1,3-propanediol, ethanol and organic acids.

The glycerol biorefinery: a purpose for Brazilian biodiesel production

“…Similarly to the sugarcane biorefinery, it has been proposed for glycerol biorefinery [28]. Glycerin may be used as raw material for the production of value-added products through chemical, biochemical, or thermochemical routes, as shown in Figure 5 [23,24,[28][29][30][31][32].…”

“…They are used to improve the nutritional profile of food products due to their low caloric content, low insulin-mediated response, and non-cariogenicity. Polyols and their derivatives also have other industrial applications, including the production of polyurethanes, plastifying agents, resins, surfactants, and intermediates for producing hydrocarbons [23,24,[28][29][30][31][32][33].…”

“…BioMCN has been producing methanol from synthesis gas obtained from glycerin since 2010 in Delfzijl (Netherlands) [35]. Figure 5 Products obtained from glycerin produced in biorefinery [23,24,[28][29][30][31][32].…”

“…Yeast and filamentous fungi convert glycerol to polyols and organic acids by Figure 6 Products obtained from glycerol bioconversion metabolism [28,29,46,47]. Products and glycerol are enclosed in boxes and the main intermediates are enclosed in circles.…”

“…Additionally, Escherichia coli and other bacteria produce lactic and glyceric acids and dihydroacetone under microaerobic conditions. Succinic acid can be produced by aerobic and microaerobic pathways, while 1,3-propanediol and ethanol can be obtained by anaerobic and microaerobic conditions [28,29,46,47].…”