Microbial Conversion of Waste Glycerol from Biodiesel Production into Value-Added Products

Abstract

Biodiesel has gained a significant amount of attention over the past decade as an environmentally friendly fuel that is capable of being utilized by a conventional diesel engine. However, the biodiesel production process generates glycerol-containing waste streams which have become a disposal issue for biodiesel plants and generated a surplus of glycerol. A value-added opportunity is needed in order to compensate for disposal-associated costs. Microbial conversions from glycerol to valuable chemicals performed by various bacteria, yeast, fungi, and microalgae are discussed in this review paper, as well as the possibility of extending these conversions to microbial electrochemical technologies.

l-Lactic acid production from glycerol coupled with acetic acid metabolism by Enterococcus faecalis without carbon loss

“…Moreover, different compositions of crude glycerol affect several fermentative productions (9). Several papers also reported the conversions of crude glycerol derived from a biodiesel production to lactic acid (13,30). Therefore, the effect of crude glycerol on fermentation by strain QU 11 must be examined, in order to determine its applicability to industrial lactic acid production.…”

Castor oil as a potential renewable resource for the production of functional materials

“…Examples of such applications include but are not limited to the use of crude glycerol in animal feeds both for ruminants and non ruminants animals [46]. Feed stock for fermentative production 1,3-propanediol by Klebsiella pneumonia [47], biosynthesis of citric acid from crude glycerol by Yarrowia lipolytica ACA-DC 50109 [46] and fermentative conversion of crude glycerol to hydrogen by the bacterium Rhodopseudomonas palustris [48,49,50]. Glycerol can also be a good source of various solvents such as propylene glycols, glycerol ethers and esters.…”

Strategies of preserving lipids in microorganism after fermentation

“…Glycerol consumed by most of the yeast is through active transport, which requires energy (Kayingo et al, 2009;Ferreira et al, 2005;Li et al, 2013;Morales-Sanchez et al, 2013). When cells were exposed to anaerobic condition for a longer time (up to 2 h), the cell became weak and started to consume the body lipid for their survival rather than consuming extracellular glycerol and other nutrients.…”