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Difference between revisions of "Enzymatic processes"
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→Enzymatic pre-treatment (biological pre-treatment)
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=== Enzymatic pre-treatment (biological pre-treatment) === | === Enzymatic pre-treatment (biological pre-treatment) === | ||
Biological pre-treatment systems rely on biological agents (e.g., enzymes) to delignify lignocellulose and make the process of enzymatic hydrolysis more convenient. The effect of enzymes on the lignocellulosic biomass depends on the type of enzymes as well as the composition of the biomass being treated. This is due to enzyme specificity in terms of the type of the reactions that they catalyze. Laccase, manganese peroxide and versatile peroxide are enzymes that are used extensively to treat the lignocellulosic substrate. Biological pretreatment of LCB is often knows as a simple, inexpensive, selective, and environmentally-friendly technology. This is mainly due to the fact that biological pretreatment does not require high energy inputs or chemicals addition. Furthermore, enzymatic treatment has found success in the removal of toxic inhibitory compounds (i.e., complete removal of phenolic compounds). | |||
=== Enzymatic hydrolysis === | === Enzymatic hydrolysis === | ||
Enzymatic hydrolysis processes allow to produce monomeric sugars from (ligno)cellulosic biomass by using specific enzymes (i.e. cellulases and hemicellulases) able to break down the chemical bonds in cellulose and hemicellulose polymers. Several factors can affect the efficiency of this process: accessible surface area and crystallinity of the biomass, as well as pH, time and temperatures of the process<ref>{{Cite journal|title=Investigation of Enzymatic Hydrolysis of Coffee Silverskin Aimed at the Production of Butanol and Succinic Acid by Fermentative Processes|year=2019-06-01|author=Saverio Niglio, Alessandra Procentese, Maria Elena Russo, Giovanni Sannia, Antonio Marzocchella|journal=BioEnergy Research|volume=12|issue=2|page=312–324|doi=10.1007/s12155-019-09969-6}}</ref>. Enzymatic hydrolysis is gaining increased attention with respect to acid hydrolysis due to equipment corrosion, energy consumption, non-recyclability of reagents, fermentation inhibitors production during acid hydrolysis <ref>{{Cite journal|title=Enzymatic hydrolysis of lignocellulosic biomass: converting food waste in valuable products|year=2015-02-01|author=Gabriela Piccolo Maitan-Alfenas, Evan Michael Visser, Valéria Monteze Guimarães|journal=Current Opinion in Food Science|volume=1|page=44–49|doi=10.1016/j.cofs.2014.10.001}}</ref>. To increase the hydrolysis efficiency, a pretreatment step prior to enzymatic reaction is usually required due to the complex lignocellulosic biomass composition ([[Primary processing]]). | Enzymatic hydrolysis processes allow to produce monomeric sugars from (ligno)cellulosic biomass by using specific enzymes (i.e. cellulases and hemicellulases) able to break down the chemical bonds in cellulose and hemicellulose polymers. Several factors can affect the efficiency of this process: accessible surface area and crystallinity of the biomass, as well as pH, time and temperatures of the process<ref>{{Cite journal|title=Investigation of Enzymatic Hydrolysis of Coffee Silverskin Aimed at the Production of Butanol and Succinic Acid by Fermentative Processes|year=2019-06-01|author=Saverio Niglio, Alessandra Procentese, Maria Elena Russo, Giovanni Sannia, Antonio Marzocchella|journal=BioEnergy Research|volume=12|issue=2|page=312–324|doi=10.1007/s12155-019-09969-6}}</ref>. Enzymatic hydrolysis is gaining increased attention with respect to acid hydrolysis due to equipment corrosion, energy consumption, non-recyclability of reagents, fermentation inhibitors production during acid hydrolysis <ref>{{Cite journal|title=Enzymatic hydrolysis of lignocellulosic biomass: converting food waste in valuable products|year=2015-02-01|author=Gabriela Piccolo Maitan-Alfenas, Evan Michael Visser, Valéria Monteze Guimarães|journal=Current Opinion in Food Science|volume=1|page=44–49|doi=10.1016/j.cofs.2014.10.001}}</ref>. To increase the hydrolysis efficiency, a pretreatment step prior to enzymatic reaction is usually required due to the complex lignocellulosic biomass composition ([[Primary processing]]). | ||