Extraction of Sugars from Food Wastes
Due to the rich organic content of food wastes, research has been directed at the
possibilities of extraction of sugars from food wastes for production of fuels and
chemicals. To extract sugars from food wastes, pretreatment step is necessary. Dilute
acid pretreatment yields more sugars than other methods. Similarly, amylase enzyme
digestion leads to production of glucose, fructose, galactose, and ribose. Such sugars
can then be used to make platform chemicals, fuels, and food additives. It is worth
noting that during any pretreatment either it be chemical, physical, or biological,
product recovery should be maximum (Dahiya et al. 2018).
Biohydrogen
Highly degradable organic material content in food wastes makes it a potential
candidate for biohydrogen production. Biological production of hydrogen involves
photo-fermentation, biophotolysis, and anaerobic fermentation. Biohydrogen production using anaerobic fermentation is directly dependent on nature and property of
microbial inoculum, type of treatment adopted, pH, inclusion of inducer, design of
bioreactor, etc. In addition, integration of anaerobic fermentation with photofermentation to increase the yield is an additional option. Similarly fusing dark
and photo-fermentation also increases the yield of hydrogen fermentation (Arancon
et al. 2013; Maina et al. 2017; Mirabella et al. 2014).
Biomethane
The most preferred technology for energy generation from food wastes is methane
production through anaerobic digestion. The major bottleneck while using food
waste as a substrate is their rich nutrient content and foaming in the reactor. To
overcome such shortcomings process should be optimized with better C/N ratio,
newer reactor design, co-digestion with other wastes to improve methane yield
(Bhatia et al. 2018; Jobard et al. 2017; Marin-Batista et al. 2019).
Biohythane
Biohythane is a combined fuel of methane and hydrogen prepared at 1:4 ratio to
improve the calorific value of fuels. Such type of adding a small percentage of
hydrogen with methane improves efficiency of methane fuels. Food wastes as a
source of biohythane production has received attention and semi-pilot scale studies
reveal that they are the good source for production of biohythane.
Volatile Fatty Acids
During the generation of H 2 production, a combination of short chain volatile fatty
acids as co-products are generated under anaerobic fermentation. Currently these
volatile fatty acids are produced from petroleum refinery and not benign to the
environment. Hence volatile fatty acids generated from the anaerobic fermentation
of food waste has got renewed interest. Production of volatile fatty acids has
numerous advantages in textile, pharmaceutical, and food industries (Posmanik
et al. 2017).
5 Valorization of Biowastes into Food, Fuels, and Chemicals: Towards Sustainable. . .
95
Due to the rich organic content of food wastes, research has been directed at the
possibilities of extraction of sugars from food wastes for production of fuels and
chemicals. To extract sugars from food wastes, pretreatment step is necessary. Dilute
acid pretreatment yields more sugars than other methods. Similarly, amylase enzyme
digestion leads to production of glucose, fructose, galactose, and ribose. Such sugars
can then be used to make platform chemicals, fuels, and food additives. It is worth
noting that during any pretreatment either it be chemical, physical, or biological,
product recovery should be maximum (Dahiya et al. 2018).
Biohydrogen
Highly degradable organic material content in food wastes makes it a potential
candidate for biohydrogen production. Biological production of hydrogen involves
photo-fermentation, biophotolysis, and anaerobic fermentation. Biohydrogen production using anaerobic fermentation is directly dependent on nature and property of
microbial inoculum, type of treatment adopted, pH, inclusion of inducer, design of
bioreactor, etc. In addition, integration of anaerobic fermentation with photofermentation to increase the yield is an additional option. Similarly fusing dark
and photo-fermentation also increases the yield of hydrogen fermentation (Arancon
et al. 2013; Maina et al. 2017; Mirabella et al. 2014).
Biomethane
The most preferred technology for energy generation from food wastes is methane
production through anaerobic digestion. The major bottleneck while using food
waste as a substrate is their rich nutrient content and foaming in the reactor. To
overcome such shortcomings process should be optimized with better C/N ratio,
newer reactor design, co-digestion with other wastes to improve methane yield
(Bhatia et al. 2018; Jobard et al. 2017; Marin-Batista et al. 2019).
Biohythane
Biohythane is a combined fuel of methane and hydrogen prepared at 1:4 ratio to
improve the calorific value of fuels. Such type of adding a small percentage of
hydrogen with methane improves efficiency of methane fuels. Food wastes as a
source of biohythane production has received attention and semi-pilot scale studies
reveal that they are the good source for production of biohythane.
Volatile Fatty Acids
During the generation of H 2 production, a combination of short chain volatile fatty
acids as co-products are generated under anaerobic fermentation. Currently these
volatile fatty acids are produced from petroleum refinery and not benign to the
environment. Hence volatile fatty acids generated from the anaerobic fermentation
of food waste has got renewed interest. Production of volatile fatty acids has
numerous advantages in textile, pharmaceutical, and food industries (Posmanik
et al. 2017).
5 Valorization of Biowastes into Food, Fuels, and Chemicals: Towards Sustainable. . .
95