516

33 Valorization of Waste Cooking Oil into Biodiesel, Biolubricants, and Other Products

and complete convertability into desirable endproducts. The abundance of WCO

and the chemical composition makes it a preferred feedstock for fermentative break-

down by selected microbial strains. The conversion of WCO into intermediates and

by-products is mediated by enzymatic hydrolysis preferably by enzymes like lipases.

Microbial strains of Aspergillus, Candida (C. lipolytica, C. bombicala, and C. utilis),

and yeast (Y. lipolytica) have been commonly utilized for the enzymatic hydrolysis of

oils to obtain value-added products like biosurfactants, fatty acids, and enzymes [36].

33.4.9

Bioasphalt

Bituminous asphalt binder is produced from crude oil. The generation of bituminous

asphalt binder is costly, and the decreasing supply of crude oil has led to the need for

the synthesis of other binders as replacement for traditional asphalt binder. Asphalt

binder produced using green sustainable technology is known as bioasphalt. The

supplementation of WCO to asphalt binder produces bioasphalt binder with altered

properties of viscosity, and softening. Increasing the amount of WCO is helpful in

lowering the viscosity and enhancing the penetration property of asphalt binder [37].

33.4.10

Bioplasticizers

Plasticizers have been frequently employed in polymer industries as an important

part of synthesis reaction. However, the use of versatile plasticizers is restricted

owing to their accumulation in the environments due to low biodegradability pro-

file. This is mainly true for plasticizers like phthalate esters. Recently, bioplasticizers

or plasticizers produced from natural sources are being widely explored. Several

raw material sources for generating bio-based plasticizers are being scrutinized.

Different vegetable cooking oils like castor oil, soyabean oil, etc., have been reacted

and derivatized to yield acetylated, methyl-epoxylated, and amyl-epoxylated oil

derivatives. However, the high costs of the oils have restricted their use. Hence, the

epoxidation of WCO has been attempted to overcome the issue of environmental

accumulation and contribution to pollution [38].

33.4.11

Biosolvent

The chemical composition of WCO imparts it with solvent properties for certain

organic molecules. The property of certain classes of WCOs to solubilize volatile haz-

ardous organic compounds and hydrocarbons can be exploited by designing effective

bioreactors enriched with processed WCO and capable of entrapping and degrad-

ing hazardous volatile molecules, emission fogs, and hydrocarbons using suitable

microbial strains [39].

33.5

Conclusion

One side, the growing global burden of environmental pollution caused by abun-

dant production of WCO and on the other side natural oil resources depletion can be