land, time, labour, and no seasonal disturbances. Microbial biodiesel can be produced significantly under controlled conditions. Although several research efforts
are still needed to commercialize this technology on larger scale. Biomass to
biodiesel continues to be an important source of energy in the recent years (Dahiya
et al. 2018).
5.2.1.4 Biohydrogen Production from Biomass
In the current wave of renewable energy generation out of wastes, anaerobic
digestion, municipal solid waste, organic waste, agricultural waste, waste water,
and sludge are considered as renewable source of biohydrogen production. Although
the continuous production of biohydrogen has some disadvantages such as low H 2
yields, the technology can be improved by mixing photosynthetic microbes with
anaerobes to degrade carbon rich and less toxic raw materials. Under anaerobic
conditions, hydrogen production proceeds with photo fermentative as well as dark
fermentation (Balan 2014). Biohydrogen production is an anerobic fermentation of
organic substances. The most studied anaerobic bacteria Clostridium butyricum can
serve as a candidate for biohydrogen production. The theoretical yields of hydrogen
is 4 mol of H 2 per mole of glucose or 2 mol of H 2 per mole of acetate. In order to be
competitive with other biofuels, the H 2 production should be enhanced by isolation
and identification of novel microorganism with high titres, bioreactor designs, use of
mixed culture, and more advanced phototrophic microorganism for higher yields
(Venkata Mohan et al. 2016).
5.2.1.5 Bulk Chemicals from Biomass
As mentioned biomass constitutes a largest renewable resource for chemicals production. There has been renewed interest to produce fine chemicals and platform
chemicals from biomass. Although the concept is promising, and high value added
products can be generated, the industry must also think of producing bulk chemicals
initially to sustain its production (Ahorsu et al. 2018; Appels and Dewil 2012;
Balboa et al. 2015). The major limitation with fine chemicals is that they have
very small market. On the other hand, chemicals such as surfactants, plastic
monomers, lubricants, fibres, and industrial solvents serve as bulk chemicals with
huge market potential. High value added fuels and chemicals currently replace
300 million gallons of petroleum per year. The market for high value chemicals is
growing rapidly and will have a better future in contributing to economy of the
nation (Biddy et al. 2016).
For the production of bulk and fine chemicals, focus must be paid to use the food
processing waste. The residues left on the field although in enormous quantity, they
may be preferred to be retained on the field, as they add more value to soil. On
volume basis, rice husks and sugarcane bagasse are the two important processed
residues from rice processing plant and sugar industry, respectively. These two high
volume renewable sources are available for production of fuels and chemicals.
Organic fraction of municipal solid waste is also another important source of
biowastes that can be efficiently transformed into fuels and chemicals (Gallezot
2012).
5 Valorization of Biowastes into Food, Fuels, and Chemicals: Towards Sustainable. . .
91
are still needed to commercialize this technology on larger scale. Biomass to
biodiesel continues to be an important source of energy in the recent years (Dahiya
et al. 2018).
5.2.1.4 Biohydrogen Production from Biomass
In the current wave of renewable energy generation out of wastes, anaerobic
digestion, municipal solid waste, organic waste, agricultural waste, waste water,
and sludge are considered as renewable source of biohydrogen production. Although
the continuous production of biohydrogen has some disadvantages such as low H 2
yields, the technology can be improved by mixing photosynthetic microbes with
anaerobes to degrade carbon rich and less toxic raw materials. Under anaerobic
conditions, hydrogen production proceeds with photo fermentative as well as dark
fermentation (Balan 2014). Biohydrogen production is an anerobic fermentation of
organic substances. The most studied anaerobic bacteria Clostridium butyricum can
serve as a candidate for biohydrogen production. The theoretical yields of hydrogen
is 4 mol of H 2 per mole of glucose or 2 mol of H 2 per mole of acetate. In order to be
competitive with other biofuels, the H 2 production should be enhanced by isolation
and identification of novel microorganism with high titres, bioreactor designs, use of
mixed culture, and more advanced phototrophic microorganism for higher yields
(Venkata Mohan et al. 2016).
5.2.1.5 Bulk Chemicals from Biomass
As mentioned biomass constitutes a largest renewable resource for chemicals production. There has been renewed interest to produce fine chemicals and platform
chemicals from biomass. Although the concept is promising, and high value added
products can be generated, the industry must also think of producing bulk chemicals
initially to sustain its production (Ahorsu et al. 2018; Appels and Dewil 2012;
Balboa et al. 2015). The major limitation with fine chemicals is that they have
very small market. On the other hand, chemicals such as surfactants, plastic
monomers, lubricants, fibres, and industrial solvents serve as bulk chemicals with
huge market potential. High value added fuels and chemicals currently replace
300 million gallons of petroleum per year. The market for high value chemicals is
growing rapidly and will have a better future in contributing to economy of the
nation (Biddy et al. 2016).
For the production of bulk and fine chemicals, focus must be paid to use the food
processing waste. The residues left on the field although in enormous quantity, they
may be preferred to be retained on the field, as they add more value to soil. On
volume basis, rice husks and sugarcane bagasse are the two important processed
residues from rice processing plant and sugar industry, respectively. These two high
volume renewable sources are available for production of fuels and chemicals.
Organic fraction of municipal solid waste is also another important source of
biowastes that can be efficiently transformed into fuels and chemicals (Gallezot
2012).
5 Valorization of Biowastes into Food, Fuels, and Chemicals: Towards Sustainable. . .
91