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5.4 Factors Influencing Polyhydroxyalkanoates Production,
Accumulation, and Composition
5.4.1 Strains of Bacteria
There are many microorganisms with the ability of producing polyhydroxyalkanoates from carbon sources. Many groups of naturally occurring prokaryotes, such as
bacteria and archaea, can decompose and consume polyhydroxyalkanoates for their
survival and growth (Dietrich et al. 2017). There are more than 300 microorganisms
with ability to produce polyhydroxyalkanoates (Choi and Lee 1999). However, the
main issue is the selection of bacterial strains with high polyhydroxyalkanoates
production rates and accumulation capabilities. In the past, polyhydroxyalkanoates
have been industrially produced by pure cultures including Azotobacter vinelandii,
Azohydromonas lata, and Pseudomonas oleovorans at high concentrations
(Salehizadeh and van Loosdrecht 2004; Choi and Lee 1999). The most widely used
wild-type strain for scl-polyhydroxyalkanoates is Cupriavidus necator due to its
well-known metabolism, its ability to grow at high cell density (100–200 g/L), and
its high cellular polyhydroxyalkanoates content (75–80%) (Dietrich et al. 2017).
For mcl-polyhydroxyalkanoates production, the most commonly employed bacteria
is Aeromonas hydrophila (Dietrich et al. 2017; Choi and Lee 1999). Escherichia
coli bacteria is the most widely used recombinant bacteria in the industry because
of its easy genetic manipulation, fast growth, and ability to use cheap carbon sources
(Dietrich et al. 2017).
Pseudomonas have a wide catabolic versatility, which enables them to reduce
diverse carbon sources such as toluene, benzene, and ethylbenzene (Kourmentza
et al. 2017). They also have the ability to grow in soils polluted with petroleum or
petroleum-based hydrocarbons and therefore have promise for polyhydroxyalkanoates production using industrial wastewaters including petrochemical, oil, and gas
industry wastewaters (Goudarztalejerdi et al. 2015). Pseudomonas were able to produce a high content of polyhydroxyalkanoates at 65.8% from decanoic acid as the
sole carbon source, while benzene and toluene produced 19.1% and 58.9% under a
continuous feeding condition, respectively (Kourmentza et al. 2017).
Among the microorganisms capable of anaerobic storage of carbon sources are
the well-known polyphosphate-accumulating organisms and glycogen- accumulating
organisms. Polyphosphate-accumulating organisms are one of the well-known
polyhydroxyalkanoates producers, not due to their high production rates or yields
but due to their competitive advantage associated with their ability to utilize energy
stored as polyphosphate to convert and store external substrate in the form of polyhydroxyalkanoates when no electron acceptor for energy generation is available
(Salehizadeh and van Loosdrecht 2004). This metabolism is widely exploited for
phosphorus removal from wastewaters allowing easy enrichment in mixed cultures.
Glycogen-accumulating organisms are a natural competitor to polyphosphateaccumulating organisms and produce polyhydroxyalkanoates from fermentation
products and from stored glycogen (Salehizadeh and van Loosdrecht 2004). The
5 Integration of Polyhydroxyalkanoates Production with Industrial Wastewater…
5.4 Factors Influencing Polyhydroxyalkanoates Production,
Accumulation, and Composition
5.4.1 Strains of Bacteria
There are many microorganisms with the ability of producing polyhydroxyalkanoates from carbon sources. Many groups of naturally occurring prokaryotes, such as
bacteria and archaea, can decompose and consume polyhydroxyalkanoates for their
survival and growth (Dietrich et al. 2017). There are more than 300 microorganisms
with ability to produce polyhydroxyalkanoates (Choi and Lee 1999). However, the
main issue is the selection of bacterial strains with high polyhydroxyalkanoates
production rates and accumulation capabilities. In the past, polyhydroxyalkanoates
have been industrially produced by pure cultures including Azotobacter vinelandii,
Azohydromonas lata, and Pseudomonas oleovorans at high concentrations
(Salehizadeh and van Loosdrecht 2004; Choi and Lee 1999). The most widely used
wild-type strain for scl-polyhydroxyalkanoates is Cupriavidus necator due to its
well-known metabolism, its ability to grow at high cell density (100–200 g/L), and
its high cellular polyhydroxyalkanoates content (75–80%) (Dietrich et al. 2017).
For mcl-polyhydroxyalkanoates production, the most commonly employed bacteria
is Aeromonas hydrophila (Dietrich et al. 2017; Choi and Lee 1999). Escherichia
coli bacteria is the most widely used recombinant bacteria in the industry because
of its easy genetic manipulation, fast growth, and ability to use cheap carbon sources
(Dietrich et al. 2017).
Pseudomonas have a wide catabolic versatility, which enables them to reduce
diverse carbon sources such as toluene, benzene, and ethylbenzene (Kourmentza
et al. 2017). They also have the ability to grow in soils polluted with petroleum or
petroleum-based hydrocarbons and therefore have promise for polyhydroxyalkanoates production using industrial wastewaters including petrochemical, oil, and gas
industry wastewaters (Goudarztalejerdi et al. 2015). Pseudomonas were able to produce a high content of polyhydroxyalkanoates at 65.8% from decanoic acid as the
sole carbon source, while benzene and toluene produced 19.1% and 58.9% under a
continuous feeding condition, respectively (Kourmentza et al. 2017).
Among the microorganisms capable of anaerobic storage of carbon sources are
the well-known polyphosphate-accumulating organisms and glycogen- accumulating
organisms. Polyphosphate-accumulating organisms are one of the well-known
polyhydroxyalkanoates producers, not due to their high production rates or yields
but due to their competitive advantage associated with their ability to utilize energy
stored as polyphosphate to convert and store external substrate in the form of polyhydroxyalkanoates when no electron acceptor for energy generation is available
(Salehizadeh and van Loosdrecht 2004). This metabolism is widely exploited for
phosphorus removal from wastewaters allowing easy enrichment in mixed cultures.
Glycogen-accumulating organisms are a natural competitor to polyphosphateaccumulating organisms and produce polyhydroxyalkanoates from fermentation
products and from stored glycogen (Salehizadeh and van Loosdrecht 2004). The
5 Integration of Polyhydroxyalkanoates Production with Industrial Wastewater…