• Because LPMOs have oxidative property, they are not compatible with various
simultaneous saccharification and fermentation schemes that require reduction
conditions (Olofsson et al. 2008; Rana et al. 2014).
• The oxidized sugar products that enzymes release are not effectively used by
microorganisms; hence microbial growth can be inhibited (Kaur et al. 2006;
Decker et al. 2017).
• The autocatalytic inactivation of LPMO: The effect of the substrate is very
important in the stability of LMPOs. LPMOs are protected from auto-oxidative
inactivation when attached to the substrate. LPMOs are inactivated when the
amount of substrate is reduced (Courtade et al. 2018).
• The stability of the enzyme: Since the LPMOs are extracellular enzymes, they are
usually stabilized by disulfide links. In the presence of Cu, they are thermostable
above 60
C (Hemsworth et al. 2013; Hemsworth et al. 2015).
• Hydrogen peroxide production of the oxidative enzymes may cause them to lose
their activities (Valderrama et al. 2002).
• Due to the fact that most of the substrates are insoluble, some analytical problems
arise (Forsberg et al. 2019).
• The kinetic data is scarce, and obtaining these data experimentally is hard
(Forsberg et al. 2019).
• Adding LPMOs in commercial cellulolytic enzyme cocktails for the saccharification of pretreated plant residues economically contributes to the process cost
(Teter 2012; Johansen 2016). However, phenolic compounds and high concentration of oxygen may cause the inactivation of the cellulase cocktails due to
LPMO (Kim et al. 2011; Ximenes et al. 2011).
9.5 Enzymatic Cocktails
Although the search for producing alternative fuels out of lignocellulosic biomass
has begun long ago, there are still many challenges in applying and maintaining the
process commercially. Various enzymes are needed to transform lignocellulosic
materials or microalgae into fully fermented sugars (Yeoman et al. 2010; Chandel
et al. 2012; Zabed et al. 2019). However, a single microbial organism that can
sufficiently produce all the required enzymes for producing the biomass conversion
has not been defined yet (Adsul et al. 2020).
Industrial enzyme production (depending on the enzyme source, production
approaches, country, etc.) is a costly process; furthermore completing the process
in short time is important (Klein-Marcuschamer et al. 2012; Binod et al. 2019). In
recent years, many researchers and enzyme-producing biotechnology companies
(e.g., Dupont-Genencor, Dyadic and Novozyme) have focused on “enzymatic cocktails” in order to develop enzymatic hydrolysis processes (Agrawal et al. 2018;
Sanhueza et al. 2018).
Preparation of an appropriate enzymatic preparate requires knowledge about
particularly the biomass composition, followed by the type of the applied
282
T. Karaytuğ et al.
simultaneous saccharification and fermentation schemes that require reduction
conditions (Olofsson et al. 2008; Rana et al. 2014).
• The oxidized sugar products that enzymes release are not effectively used by
microorganisms; hence microbial growth can be inhibited (Kaur et al. 2006;
Decker et al. 2017).
• The autocatalytic inactivation of LPMO: The effect of the substrate is very
important in the stability of LMPOs. LPMOs are protected from auto-oxidative
inactivation when attached to the substrate. LPMOs are inactivated when the
amount of substrate is reduced (Courtade et al. 2018).
• The stability of the enzyme: Since the LPMOs are extracellular enzymes, they are
usually stabilized by disulfide links. In the presence of Cu, they are thermostable
above 60
C (Hemsworth et al. 2013; Hemsworth et al. 2015).
• Hydrogen peroxide production of the oxidative enzymes may cause them to lose
their activities (Valderrama et al. 2002).
• Due to the fact that most of the substrates are insoluble, some analytical problems
arise (Forsberg et al. 2019).
• The kinetic data is scarce, and obtaining these data experimentally is hard
(Forsberg et al. 2019).
• Adding LPMOs in commercial cellulolytic enzyme cocktails for the saccharification of pretreated plant residues economically contributes to the process cost
(Teter 2012; Johansen 2016). However, phenolic compounds and high concentration of oxygen may cause the inactivation of the cellulase cocktails due to
LPMO (Kim et al. 2011; Ximenes et al. 2011).
9.5 Enzymatic Cocktails
Although the search for producing alternative fuels out of lignocellulosic biomass
has begun long ago, there are still many challenges in applying and maintaining the
process commercially. Various enzymes are needed to transform lignocellulosic
materials or microalgae into fully fermented sugars (Yeoman et al. 2010; Chandel
et al. 2012; Zabed et al. 2019). However, a single microbial organism that can
sufficiently produce all the required enzymes for producing the biomass conversion
has not been defined yet (Adsul et al. 2020).
Industrial enzyme production (depending on the enzyme source, production
approaches, country, etc.) is a costly process; furthermore completing the process
in short time is important (Klein-Marcuschamer et al. 2012; Binod et al. 2019). In
recent years, many researchers and enzyme-producing biotechnology companies
(e.g., Dupont-Genencor, Dyadic and Novozyme) have focused on “enzymatic cocktails” in order to develop enzymatic hydrolysis processes (Agrawal et al. 2018;
Sanhueza et al. 2018).
Preparation of an appropriate enzymatic preparate requires knowledge about
particularly the biomass composition, followed by the type of the applied
282
T. Karaytuğ et al.