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who have now made all cosmetic packaging from polyhydroxyalkanoates, a bioplastic derived from fermentation or plants (Vandi et al. 2018), and Coca-Cola, who
is blending bioplastics into their current drink bottles and plans to produce bioplastic-only bottles in the future (The Coca-Cola Company 2017). Such examples provide strong evidence for a growing market and uptake of bioplastic-based products
and their potential importance in the future polymer industry.
5.1.2 Bioplastics and Polyhydroxyalkanoates
Polyhydroxyalkanoates are a promising bio-derived, biocompatible, biodegradable,
and chemically diverse polyester material (Serafim et al. 2008). They are synthesized naturally in the prokaryotic microbial cells under conditions that induce a
need for carbon, energy, or reducing-power storage (Salehizadeh and van Loosdrecht
2004; Castilho et al. 2009). In addition, they can also be produced by plants.
However, due to the low yield in plants of less than 10% of dry weight polyhydroxyalkanoates (Verlinden et al. 2007) and limited polyhydroxyalkanoates monomer
types produced (Gumel et al. 2013), bacteria are the more promising production route.
In bacteria, polyhydroxyalkanoates are produced in the process of carbon assimilation under unbalanced conditions as an intracellular storage product (Bugnicourt
et al. 2014) and can be consumed by the bacteria as an alternative carbon source in
conditions of famine (Kourmentza et al. 2017). Over 90 genera of microbial species
are known to produce polyhydroxyalkanoates and are found in a wide variety of
environments (Castilho et al. 2009). Bacteria store polyhydroxyalkanoates inside
the cell in a polymerized form (Saharan et al. 2014), and their production can reach
a yield of up to 90% of dry weight polyhydroxyalkanoates in some special cases
(Verlinden et al. 2007). They are found under different types and shapes and are
produced by different strains of bacteria and some archaea (Koller et al. 2011; Tan
et al. 2014). In fact, more than 150 different monomer units have been linked as
constituents of polyhydroxyalkanoates (Castilho et al. 2009). Hydroxybutyrate,
hydroxyvalerate, hydroxyhexanoate (Green et al. 2002), hydroxypentenoate,
hydroxyoctanoate, hydroxypropionate (Kourmentza et al. 2017), hydroxydecanoate
(Hokamura et al. 2017), and hydroxyheptanoate (Green et al. 2002) are few of the
many monomer units that can compose polyhydroxyalkanoates in addition to many
other hydroxyalkanoic acids and even some mercaptoalkanoic acids (Visakh 2014).
The general structure of polyhydroxyalkanoates is shown in Fig. 5.2. Usually, a
polyhydroxyalkanoate molecule is composed of 600 to 35,000 monomer units (Tan
et al. 2014). When various monomer types are incorporated into the chain, the properties of the polymer change including a decrease in the melting temperature, especially with the incorporation of more hydroxyvalerate units into hydroxybutyrate
units (Fradinho et al. 2014). Additionally, it was discovered that polyhydroxyalkanoates with 4-hydroxybutyrate have higher flexibility than the 3-hydroxybutyrate
(Możejko-Ciesielska and Kiewisz 2016).
5 Integration of Polyhydroxyalkanoates Production with Industrial Wastewater…
who have now made all cosmetic packaging from polyhydroxyalkanoates, a bioplastic derived from fermentation or plants (Vandi et al. 2018), and Coca-Cola, who
is blending bioplastics into their current drink bottles and plans to produce bioplastic-only bottles in the future (The Coca-Cola Company 2017). Such examples provide strong evidence for a growing market and uptake of bioplastic-based products
and their potential importance in the future polymer industry.
5.1.2 Bioplastics and Polyhydroxyalkanoates
Polyhydroxyalkanoates are a promising bio-derived, biocompatible, biodegradable,
and chemically diverse polyester material (Serafim et al. 2008). They are synthesized naturally in the prokaryotic microbial cells under conditions that induce a
need for carbon, energy, or reducing-power storage (Salehizadeh and van Loosdrecht
2004; Castilho et al. 2009). In addition, they can also be produced by plants.
However, due to the low yield in plants of less than 10% of dry weight polyhydroxyalkanoates (Verlinden et al. 2007) and limited polyhydroxyalkanoates monomer
types produced (Gumel et al. 2013), bacteria are the more promising production route.
In bacteria, polyhydroxyalkanoates are produced in the process of carbon assimilation under unbalanced conditions as an intracellular storage product (Bugnicourt
et al. 2014) and can be consumed by the bacteria as an alternative carbon source in
conditions of famine (Kourmentza et al. 2017). Over 90 genera of microbial species
are known to produce polyhydroxyalkanoates and are found in a wide variety of
environments (Castilho et al. 2009). Bacteria store polyhydroxyalkanoates inside
the cell in a polymerized form (Saharan et al. 2014), and their production can reach
a yield of up to 90% of dry weight polyhydroxyalkanoates in some special cases
(Verlinden et al. 2007). They are found under different types and shapes and are
produced by different strains of bacteria and some archaea (Koller et al. 2011; Tan
et al. 2014). In fact, more than 150 different monomer units have been linked as
constituents of polyhydroxyalkanoates (Castilho et al. 2009). Hydroxybutyrate,
hydroxyvalerate, hydroxyhexanoate (Green et al. 2002), hydroxypentenoate,
hydroxyoctanoate, hydroxypropionate (Kourmentza et al. 2017), hydroxydecanoate
(Hokamura et al. 2017), and hydroxyheptanoate (Green et al. 2002) are few of the
many monomer units that can compose polyhydroxyalkanoates in addition to many
other hydroxyalkanoic acids and even some mercaptoalkanoic acids (Visakh 2014).
The general structure of polyhydroxyalkanoates is shown in Fig. 5.2. Usually, a
polyhydroxyalkanoate molecule is composed of 600 to 35,000 monomer units (Tan
et al. 2014). When various monomer types are incorporated into the chain, the properties of the polymer change including a decrease in the melting temperature, especially with the incorporation of more hydroxyvalerate units into hydroxybutyrate
units (Fradinho et al. 2014). Additionally, it was discovered that polyhydroxyalkanoates with 4-hydroxybutyrate have higher flexibility than the 3-hydroxybutyrate
(Możejko-Ciesielska and Kiewisz 2016).
5 Integration of Polyhydroxyalkanoates Production with Industrial Wastewater…