produce some vitamins, single cell proteins, a number of antibiotics, and carboxylic
acid (Fei et al. 2014). These bacteria also produce a number of biopolymers such as
poly-β-hydroxybutyrate. Poly-β-hydroxybutyrate is the alternative option of polypropylene and can replace the use of polypropylene in the future (Fei et al. 2014; Hu
et al. 2016).
2.5.2 Biofuel from Wastewater Treatment Plant
Wastewater such as industrial wastewater and domestic waste contain enough
amount of carbon-containing compound (Zhang et al. 2014; Singh et al. 2020c).
These carbon compounds enhance the growth of microorganisms considered as
good sources for bioenergy production. The process of biofuel production and
wastewater utilization is shown in Fig. 2.6.
Sludge activation is the main stage in wastewater treatment where organic
substance oxide into CO 2 and involved in the various metabolic activity of microorganisms (Abdelaziz et al. 2013). In the domestic sludge, lipid content varies from
30 to 40% or the total organic matter. Triacylglycerols are the major component in
the lipid content present in the municipal sludge (Shreve and Brennan 2019). Several
bacteria have the capability to uptake lipid from municipal sludge or form other
carbon sources from them. These bacteria can store lipids in the intracellular space of
the cell. Triacylglycerols and wax esters and polyhydroxyalkanoates are the examples of lipids stored by the bacteria in the intracellular space (Pittman et al. 2011;
Sriwiriyarat and Randall 2005; Chinnasamy et al. 2010; Singh et al. 2016).
2.5.3 Microbial Fuel Cells (MFCs)
MFC is the bioconversion of chemical energy to electrical energy through metabolic
reactions of microorganisms (Yu et al. 2012). If devices take energy directly from
the plant cells, then they are known as plant microbial fuel cells (PMFC). The
microbial fuel cell has potential applications in the field of bioremediation of
pollutants, biosensors, wastewater treatment, biowaste conversion, and electricity
production. The hydrogenesis is the main source of electricity production. Hydrogen
molecules are generated in the microbial cell metabolism. Biohydrogen production
in the electron transport chain of microbial cells is the well known example of
biohydrogen production. These hydrogen or proton species are captured by the MFC
device and used in the generation of electricity (Singh et al. 2020e; Yadav et al.
2019; Mathuriya 2020; Balasubramaniam et al. 2020; Mani et al. 2020; Zhang et al.
2020).
2 Microbiological Aspects of Bioenergy Production: Recent Update and Future. . .
43
acid (Fei et al. 2014). These bacteria also produce a number of biopolymers such as
poly-β-hydroxybutyrate. Poly-β-hydroxybutyrate is the alternative option of polypropylene and can replace the use of polypropylene in the future (Fei et al. 2014; Hu
et al. 2016).
2.5.2 Biofuel from Wastewater Treatment Plant
Wastewater such as industrial wastewater and domestic waste contain enough
amount of carbon-containing compound (Zhang et al. 2014; Singh et al. 2020c).
These carbon compounds enhance the growth of microorganisms considered as
good sources for bioenergy production. The process of biofuel production and
wastewater utilization is shown in Fig. 2.6.
Sludge activation is the main stage in wastewater treatment where organic
substance oxide into CO 2 and involved in the various metabolic activity of microorganisms (Abdelaziz et al. 2013). In the domestic sludge, lipid content varies from
30 to 40% or the total organic matter. Triacylglycerols are the major component in
the lipid content present in the municipal sludge (Shreve and Brennan 2019). Several
bacteria have the capability to uptake lipid from municipal sludge or form other
carbon sources from them. These bacteria can store lipids in the intracellular space of
the cell. Triacylglycerols and wax esters and polyhydroxyalkanoates are the examples of lipids stored by the bacteria in the intracellular space (Pittman et al. 2011;
Sriwiriyarat and Randall 2005; Chinnasamy et al. 2010; Singh et al. 2016).
2.5.3 Microbial Fuel Cells (MFCs)
MFC is the bioconversion of chemical energy to electrical energy through metabolic
reactions of microorganisms (Yu et al. 2012). If devices take energy directly from
the plant cells, then they are known as plant microbial fuel cells (PMFC). The
microbial fuel cell has potential applications in the field of bioremediation of
pollutants, biosensors, wastewater treatment, biowaste conversion, and electricity
production. The hydrogenesis is the main source of electricity production. Hydrogen
molecules are generated in the microbial cell metabolism. Biohydrogen production
in the electron transport chain of microbial cells is the well known example of
biohydrogen production. These hydrogen or proton species are captured by the MFC
device and used in the generation of electricity (Singh et al. 2020e; Yadav et al.
2019; Mathuriya 2020; Balasubramaniam et al. 2020; Mani et al. 2020; Zhang et al.
2020).
2 Microbiological Aspects of Bioenergy Production: Recent Update and Future. . .
43