physiochemical conditions, and these enzymes find their utility in many industries
such as the biofuel, pharmaceutical, fine chemicals, and food (Singh 2012). There
are many other industries that involve the usage of extremozymes of thermophiles.
In this context, paper and bleaching industry and first- and second-generation
biofuels industries are some important examples (Morozkinaet al.2010). Starch
hydrolysis rate gets enhanced at an elevated temperature by the involvement of
amylase that has thermostability. The chances of contamination are, thereby, highly
diminished.
There are many enzymes that not only possess thermostability but can efficiently
perform in wide range of pH. These enzymes are sold by different companies by
many brand names. One such example is Fuelzyme
® (Verenium Corporation, San
Diego, CA). It is an amylase of alpha type and its source is a thermophile
Thermococcus sp. whose habitat is a deep-sea hydrothermal vent, from where it is
isolated. Mash liquefaction is mediated by Fuelzyme
® during production of ethanol.
This process releases dextrins and oligosaccharides, which possess low molecular
weight and get easily solubilized. pH range and temperature at which Fuelzyme
®
works potentially is 4.0–6.5 and 110
C, respectively (Karan et al. 2012). However,
Fuelzyme
® and Spezyme
® (DuPont-Genencor Science) are exceptionally meant for
generation of biofuel. Processing of industrial starch becomes faster when a cocktail
of theses branded enzymes is used. Amylases isolated from Bacillus sp. are found
perfect for applications during downstream process (Gabani and Singh 2013).
For an efficient bioconversion of a substrate to viable bioethanol production, it is
mandatory to utilize the entire variety of carbohydrate components present in
lignocellulosic material. D-xylose is the component of xylan. Many organisms are
reported to produce ethanol, both from D-xylose and xylan. Important ethanol
producers from these substrates are T. ethanolicus, C. thermocellum, C.
thermohydrosulfuricum
(reclassified
as
Thermoanaerobacter
thermohydrosulfuricus), T. brockii (reclassified as Thermoanaerobacter brockii),
C.
thermosaccharolyticum
(reclassified
as
Thermoanaerobacterium
thermosaccharolyticum), and T. saccharolyticum B6A. These organisms are anaerobic thermophiles that have the optimum growth temperature of 70–80
C. These
organisms have been explored from various habitats, main among which are hot
springs, paper pulp mills, and brewery wastewater. These thermophiles have potential to covert monomers of hemicelluloses like xylose, arabinose, mannose, and
galactose to ethanol, where the yield and productivity are found to be satisfactory
(Scully and Orlygsson 2015). Likewise, Kluyveromyces marxianus 6556 is also a
thermotolerant strain that has the capability to undergo simultaneous saccharification
and fermentation (SSF) of lignocellulosic agricultural residues. These species can
grow potentially well around 40
C. They can ferment the cocktail of variety of
sugars like glucose, xylose, mannose, and galactose. Some strains of this organism
are physiologically active at 52
C, where they can speedily get replicated and have
high growth rate (Rajoka et al. 2003). Xylose can get converted to ethanol under SSF
at elevated temperature, utilizing K. marxianus (Fonseca et al. 2007). K. marxianus
possesses genes that encode for many thermotolerant enzymes, viz.
cellobiohydrolase, endoglucanase, and β-glucosidase (Hong et al. 2007). When K.
3 Role of Thermophiles in Production of Aviation Biofuels: Fueling the Future
75
such as the biofuel, pharmaceutical, fine chemicals, and food (Singh 2012). There
are many other industries that involve the usage of extremozymes of thermophiles.
In this context, paper and bleaching industry and first- and second-generation
biofuels industries are some important examples (Morozkinaet al.2010). Starch
hydrolysis rate gets enhanced at an elevated temperature by the involvement of
amylase that has thermostability. The chances of contamination are, thereby, highly
diminished.
There are many enzymes that not only possess thermostability but can efficiently
perform in wide range of pH. These enzymes are sold by different companies by
many brand names. One such example is Fuelzyme
® (Verenium Corporation, San
Diego, CA). It is an amylase of alpha type and its source is a thermophile
Thermococcus sp. whose habitat is a deep-sea hydrothermal vent, from where it is
isolated. Mash liquefaction is mediated by Fuelzyme
® during production of ethanol.
This process releases dextrins and oligosaccharides, which possess low molecular
weight and get easily solubilized. pH range and temperature at which Fuelzyme
®
works potentially is 4.0–6.5 and 110
C, respectively (Karan et al. 2012). However,
Fuelzyme
® and Spezyme
® (DuPont-Genencor Science) are exceptionally meant for
generation of biofuel. Processing of industrial starch becomes faster when a cocktail
of theses branded enzymes is used. Amylases isolated from Bacillus sp. are found
perfect for applications during downstream process (Gabani and Singh 2013).
For an efficient bioconversion of a substrate to viable bioethanol production, it is
mandatory to utilize the entire variety of carbohydrate components present in
lignocellulosic material. D-xylose is the component of xylan. Many organisms are
reported to produce ethanol, both from D-xylose and xylan. Important ethanol
producers from these substrates are T. ethanolicus, C. thermocellum, C.
thermohydrosulfuricum
(reclassified
as
Thermoanaerobacter
thermohydrosulfuricus), T. brockii (reclassified as Thermoanaerobacter brockii),
C.
thermosaccharolyticum
(reclassified
as
Thermoanaerobacterium
thermosaccharolyticum), and T. saccharolyticum B6A. These organisms are anaerobic thermophiles that have the optimum growth temperature of 70–80
C. These
organisms have been explored from various habitats, main among which are hot
springs, paper pulp mills, and brewery wastewater. These thermophiles have potential to covert monomers of hemicelluloses like xylose, arabinose, mannose, and
galactose to ethanol, where the yield and productivity are found to be satisfactory
(Scully and Orlygsson 2015). Likewise, Kluyveromyces marxianus 6556 is also a
thermotolerant strain that has the capability to undergo simultaneous saccharification
and fermentation (SSF) of lignocellulosic agricultural residues. These species can
grow potentially well around 40
C. They can ferment the cocktail of variety of
sugars like glucose, xylose, mannose, and galactose. Some strains of this organism
are physiologically active at 52
C, where they can speedily get replicated and have
high growth rate (Rajoka et al. 2003). Xylose can get converted to ethanol under SSF
at elevated temperature, utilizing K. marxianus (Fonseca et al. 2007). K. marxianus
possesses genes that encode for many thermotolerant enzymes, viz.
cellobiohydrolase, endoglucanase, and β-glucosidase (Hong et al. 2007). When K.
3 Role of Thermophiles in Production of Aviation Biofuels: Fueling the Future
75