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206 Refining Biomass Residues for Sustainable Energy and Bioproducts

this crude glycerol may be used as supplement energy source for the cattle feed
(Chung et al., 2007). At low concentration, crude glycerol can be used as a potential
ingredient source for the production of broiler feed and pig feed (Cerrate et al.,
2006; Roger et al., 1992; Della Casa et al., 2009). In broiler diets, increasing the
intake level of crude glycerol increased feed conversion ratio but did not affect
growth performance and nutrient digestibility (McLea et al., 2011).
Due to the high energy content, crude glycerol can be used as a substitute for
boiler fuel or cogeneration of electricity/thermal energy. In this case, glycerol can be
directly used in large quantities without any refining process. The presence of water
and methanol in crude glycerol restricts its usage as cofiring in thermal energy.
Apart from this, glycerol can also find its application as a plasticizer and lubri-
cant in production and as a sizing, lubricating, and softening yarn and fabrics in tex-
tile industries. It is also used as a major ingredient in toothpaste and finds its
application in preserving the moisture content of tobacco (Donkin Shawn, 2008).
Glycerol helps to increase the viscosity of the liquid drug and provides humidity to
pills with its wide application in medicine and pharmaceutical industries. Glycerin
is an excellent solvent of iodine, bromine, phenol, tannins, alkaloids, and mercury
chloride (Ampaitepin and Tetsuo, 2010).

9.5 Conclusion

Glycerol is a versatile, nontoxic, and biodegradable compound that can be converted
into numerous chemicals or bio-based products. The demand and supply of crude glyc-
erol are directly correlated with its usage and new outlets. One of the major hurdles in
the utilization of crude glycerol is that most of the microorganisms exhibit the substrate
mediated inhibition because of the copious amount of impurities present in it.
Glycerol-purification technology offers promising opportunities for the production of
high-platform chemicals from crude glycerol either by biological or chemical route.
These technologies and production of new products from glycerol help to increase the
economic status of the bio-based company for the long run. If the biodiesel industries
proceed the purification and bioconversion in the biorefineries concept, it enjoys
numerous benefits, such as zero liquid discharge, self-disposal, and purging of the risk
contamination, trailed by legal sanctions. This technology will have a great substantial
impact on the economic and environmental sectors. Thus the utilization of low-cost
crude glycerol provides the broad spectrum of option for the production of high-value
platform chemicals and also serves as a renewable building block for biorefineries.

References

Alhanash, A., Kozhevnikova, E.F., Kozhenikov, I.V., 2010. Gas phase dehydration of glyc-
erol to acrolein catalyzed by caesium heteropoly salt. Appl. Catal. 378, 11 18.