involves three main steps, i.e., pulping of lignocellulose,
bleaching of fibers, and paper production. Major types of
pulping include groundwood or mechanical pulping, chemical pulping, and the combination of both mechanical and
chemical pulping (Das and Houtman 2004). Mechanical
processes consume a considerable amount of energy during
refining steps. However, bio-pulping involves the treatment
with microbial inoculum before the refining process giving
biomass soft and porous texture. These microbial-treated
biomass chips are more effectively broken apart while the
purification process, ultimately reducing energy consumption (Bajpai 2018). Moreover, production done from
microbial treated bio-fibers exhibits improved paper properties (Akhtar 1998).
The paper industry is facing high stress due to the
increasing demand for lignocellulosic pulp, which is going
to enhance in the near future. A large number of paper and
pulp industries are using classical procedures, i.e., chemical
and/or mechanical-based pulping. These industries compete
in the international market, where the material cost and
energy determined profitability. Production of pulp requires
plenty of chemicals and electrical energy. Moreover,
bleaching processes generate a huge amount of wastewater
containing toxic effluents. These hazardous chemical-based
methodologies can be effectively replaced by bio-based
pulping strategies (Giles et al. 2011). Bio-pulping can be
successfully established in industrial sectors to save chemicals, and the use of agro-industrial waste for the extraction of
bio-fibers will significantly reduce the overall production
and process cost by improving fiber texture.
Bio-pulping includes (i) steam-based decontamination of
lignocellulosic chips from naturally occurring microorganisms and (ii) inoculum addition of selected microbe, followed by incubation for 2 weeks in an aerated chip pile.
Under specific growth conditions, i.e., optimum moisture
and temperature, fungal grows on the surface of chips and
penetrates the interior using hyphae. These hyphae start
making ligninolytic enzymes, which help in easy breakage
during subsequent refining and result in flexible and intact
bio-fibers.
Chemical-based pretreatments alter the structure of pectin
and hemicellulose. These modifications have been exploited
in the synthesis of chemo-mechanical pulps of wood chips.
This results in stronger paper products as mechanical properties are enhanced by mixing with chemical pulps. White
rot fungi exhibit the ability of bio-pulping by attaching or
creating oxalate esters (COOH groups) on carbohydrates
present in the wood. Because of the dicarboxylic nature of
oxalic acid, the insertion of one carboxylic group leaves
another group as free. Configuration of the COOH group
increases the absorbance of water, and hence, the wood
bulges, which decreases the cost of refining. The carboxylic
functional group present at the surface of fibers serves as
reinforcement between fibers, which ultimately improves the
mechanical properties of paper products (Scott et al. 1998).
4 Conclusion and Future Prospective
Today the world is facing environmental and energy disasters so it is forced to use or search for alternate uses for
renewable and natural resources by green technologies. In
this case, lignocellulosic biomass has great potential to
encounter the existing need for energy for the modern world.
All pretreatment methodologies for lignocellulose bioconversion have been recognized to be effective but it depends
upon biomass nature, global location, and its final products.
All the methods you have chosen have benefits and drawbacks but they can be overcome with advanced technology.
Any method you have selected must be put toward bearing
in mind the feedstock belongings, the budget of process, and
final product yield. It must be considered that the processing
of biomass must be handled using integrated technologies
where procedures from downstream and upstream phases are
in a solitary line.
References
Abbas, A., & Ansumali, S. (2010). Global potential of rice husk as a
renewable feedstock for ethanol biofuel production. BioEnergy
Research, 3(4), 328–334.
Abbasi, T., & Abbasi, S. (2010). Biomass energy and the environmental impacts associated with its production and utilization.
Renewable and Sustainable Energy Reviews, 14(3), 919–937.
Abu Yazid, N., et al. (2017). Solid-state fermentation as a novel
paradigm for organic waste valorization: a review. Sustainability, 9
(2), 224.
Agbor, V. B., et al. (2011). Biomass pretreatment: fundamentals toward
application. Biotechnology Advances, 29(6), 675–685.
Akhtar, M., et al. (1998). An overview of biomechanical pulping
research.
Alexandrino, A. M., et al. (2007). Aproveitamento do resíduo de laranja
para a produção de enzimas lignocelulolíticas por Pleurotus
ostreatus (Jack: Fr). Food Science and Technology, 27(2), 364–368.
Allen, S. G., et al. (2001). A comparison between hot liquid water and
steam fractionation of corn fiber. Industrial and Engineering
Chemistry Research, 40(13), 2934–2941.
Alves, E. F., et al. (2010). Carbohydrate composition of eucalyptus,
bagasse and bamboo by a combination of methods. Carbohydrate
Polymers, 82(4), 1097–1101.
Amin, F. R., et al. (2017). Pretreatment methods of lignocellulosic
biomass for anaerobic digestion. Amb Express, 7(1), 72.
Anwar, Z., Gulfraz, M., & Irshad, M. (2014). Agro-industrial
lignocellulosic biomass a key to unlock the future bio-energy: A
brief review. Journal of radiation research and applied sciences, 7
(2), 163–173.
Arevalo-Gallegos, A., et al. (2017). Lignocellulose: a sustainable
material to produce value-added products with a zero waste
approach—a review. International Journal of Biological Macromolecules, 99, 308–318.
Bioconversion of Agro-Industrial Waste into Value-Added Compounds
363
bleaching of fibers, and paper production. Major types of
pulping include groundwood or mechanical pulping, chemical pulping, and the combination of both mechanical and
chemical pulping (Das and Houtman 2004). Mechanical
processes consume a considerable amount of energy during
refining steps. However, bio-pulping involves the treatment
with microbial inoculum before the refining process giving
biomass soft and porous texture. These microbial-treated
biomass chips are more effectively broken apart while the
purification process, ultimately reducing energy consumption (Bajpai 2018). Moreover, production done from
microbial treated bio-fibers exhibits improved paper properties (Akhtar 1998).
The paper industry is facing high stress due to the
increasing demand for lignocellulosic pulp, which is going
to enhance in the near future. A large number of paper and
pulp industries are using classical procedures, i.e., chemical
and/or mechanical-based pulping. These industries compete
in the international market, where the material cost and
energy determined profitability. Production of pulp requires
plenty of chemicals and electrical energy. Moreover,
bleaching processes generate a huge amount of wastewater
containing toxic effluents. These hazardous chemical-based
methodologies can be effectively replaced by bio-based
pulping strategies (Giles et al. 2011). Bio-pulping can be
successfully established in industrial sectors to save chemicals, and the use of agro-industrial waste for the extraction of
bio-fibers will significantly reduce the overall production
and process cost by improving fiber texture.
Bio-pulping includes (i) steam-based decontamination of
lignocellulosic chips from naturally occurring microorganisms and (ii) inoculum addition of selected microbe, followed by incubation for 2 weeks in an aerated chip pile.
Under specific growth conditions, i.e., optimum moisture
and temperature, fungal grows on the surface of chips and
penetrates the interior using hyphae. These hyphae start
making ligninolytic enzymes, which help in easy breakage
during subsequent refining and result in flexible and intact
bio-fibers.
Chemical-based pretreatments alter the structure of pectin
and hemicellulose. These modifications have been exploited
in the synthesis of chemo-mechanical pulps of wood chips.
This results in stronger paper products as mechanical properties are enhanced by mixing with chemical pulps. White
rot fungi exhibit the ability of bio-pulping by attaching or
creating oxalate esters (COOH groups) on carbohydrates
present in the wood. Because of the dicarboxylic nature of
oxalic acid, the insertion of one carboxylic group leaves
another group as free. Configuration of the COOH group
increases the absorbance of water, and hence, the wood
bulges, which decreases the cost of refining. The carboxylic
functional group present at the surface of fibers serves as
reinforcement between fibers, which ultimately improves the
mechanical properties of paper products (Scott et al. 1998).
4 Conclusion and Future Prospective
Today the world is facing environmental and energy disasters so it is forced to use or search for alternate uses for
renewable and natural resources by green technologies. In
this case, lignocellulosic biomass has great potential to
encounter the existing need for energy for the modern world.
All pretreatment methodologies for lignocellulose bioconversion have been recognized to be effective but it depends
upon biomass nature, global location, and its final products.
All the methods you have chosen have benefits and drawbacks but they can be overcome with advanced technology.
Any method you have selected must be put toward bearing
in mind the feedstock belongings, the budget of process, and
final product yield. It must be considered that the processing
of biomass must be handled using integrated technologies
where procedures from downstream and upstream phases are
in a solitary line.
References
Abbas, A., & Ansumali, S. (2010). Global potential of rice husk as a
renewable feedstock for ethanol biofuel production. BioEnergy
Research, 3(4), 328–334.
Abbasi, T., & Abbasi, S. (2010). Biomass energy and the environmental impacts associated with its production and utilization.
Renewable and Sustainable Energy Reviews, 14(3), 919–937.
Abu Yazid, N., et al. (2017). Solid-state fermentation as a novel
paradigm for organic waste valorization: a review. Sustainability, 9
(2), 224.
Agbor, V. B., et al. (2011). Biomass pretreatment: fundamentals toward
application. Biotechnology Advances, 29(6), 675–685.
Akhtar, M., et al. (1998). An overview of biomechanical pulping
research.
Alexandrino, A. M., et al. (2007). Aproveitamento do resíduo de laranja
para a produção de enzimas lignocelulolíticas por Pleurotus
ostreatus (Jack: Fr). Food Science and Technology, 27(2), 364–368.
Allen, S. G., et al. (2001). A comparison between hot liquid water and
steam fractionation of corn fiber. Industrial and Engineering
Chemistry Research, 40(13), 2934–2941.
Alves, E. F., et al. (2010). Carbohydrate composition of eucalyptus,
bagasse and bamboo by a combination of methods. Carbohydrate
Polymers, 82(4), 1097–1101.
Amin, F. R., et al. (2017). Pretreatment methods of lignocellulosic
biomass for anaerobic digestion. Amb Express, 7(1), 72.
Anwar, Z., Gulfraz, M., & Irshad, M. (2014). Agro-industrial
lignocellulosic biomass a key to unlock the future bio-energy: A
brief review. Journal of radiation research and applied sciences, 7
(2), 163–173.
Arevalo-Gallegos, A., et al. (2017). Lignocellulose: a sustainable
material to produce value-added products with a zero waste
approach—a review. International Journal of Biological Macromolecules, 99, 308–318.
Bioconversion of Agro-Industrial Waste into Value-Added Compounds
363