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Author:Kankaanpää, Anna
Title:Entsyymi-inhibitio lignoselluloosaperäisen etanolin tuotannossa
Enzyme inhibition in lignocellulosic ethanol production
Publication type:Master's thesis
Publication year:2014
Pages:vii + 117 s. + liitt. 3      Language:   fin
Department/School:Biotekniikan ja kemian tekniikan laitos
Main subject:Biotekniikka ja elintarviketekniikka   (KE3002)
Supervisor:Ojamo, Heikki
Instructor:Granström, Tom ; Maunuksela, Jyri
Electronic version URL: http://urn.fi/URN:NBN:fi:aalto-201409172615
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
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Location:P1 Ark Aalto  1689   | Archive
Keywords:enzyme
cellulase
enzyme inhibition
lignocellulosic ethanol
entsyymi
sellulaasi
entsyymi-inhibitio
lignoselluloosa
etanoli
Abstract (eng):The complex structure of lignocellulose causes challenges for its enzymatic hydrolysis.
The pretreatment required to unravel the lignocellulosic matrix releases compounds that potentially cause enzyme inhibition during the subsequent hydrolysis.
Additionally, the enzymes are affected by end-product inhibition as well as lignin, which unproductively adsorbs the proteins and gives structural protection for the cellulose chains.
In order to optimize the enzymatic hydrolysis of lignocellulosic materials, potential inhibitors need to be recognized and their inhibitory effect on enzymatic hydrolysis fully understood.
In this thesis, an extensive study was carried out in order to explore the challenges that arise in the enzymatic hydrolysis of wood-derived material.
In the theoretical study section, the structure of lignocellulose and the function of the cellulolytic enzymes are characterized.
The most common inhibitors present in the enzymatic hydrolysis of lignocellulosic raw materials are also described.
In the experimental study section, small scale pretreatments were done for woody biomass in order to find out the potential inhibitors formed during the treatment.
Based on these results, long-term and short-term hydrolysis experiments were carried out in the presence of the selected inhibitors.
According to this study, inhibitions caused by glucose and lignin are the most significant.
The presence of these compounds during hydrolysis should be avoided or prevented.
Inhibitions caused by different monosaccharides and phenolic compounds are noteworthy as well.
Ethanol is significant inhibitor, if its target concentration during hydrolysis is high.
Inhibition caused by furanic compounds and carboxylic acids was discovered to cause problems only when their respective concentrations were significant.
A major conclusion of this study is that the different phenomena and mechanisms involved in lignocellulose hydrolysis need to be further researched.
Abstract (fin):Lignoselluloosan monimutkainen rakenne tuo erityishaasteita materiaalin entsymaattiseen hydrolyysiin.
Ennen hydrolyysiä tehtävä esikäsittely vapauttaa yhdisteitä, jotka inhiboivat entsyymien toimintaa hydrolyysin aikana.
Lisäksi entsyymien toimintaa rajoittaa lopputuoteinhibitio sekä lignoselluloosan sisältämä ligniini, joka inhiboi entsyymejä sitomalla niitä ja suojaamalla rakenteellisesti selluloosaketjuja.
Entsymaattisen hydrolyysin optimoimiseksi on tunnistettava potentiaaliset inhibiittorit ja ymmärrettävä niiden aiheuttamien inhibitioiden vaikutus entsymaattiselle hydrolyysille.
Tässä työssä tutustutaan kattavasti erityisesti puuperäisen lignoselluloosamateriaalin hydrolyysin yhteydessä esiintyviin haasteisiin.
Teoriaosiossa kuvataan lignoselluloosan rakenne ja sitä hydrolysoivien entsyymien toiminta.
Lisäksi esitellään yleisimmät lignoselluloosaperäisen raaka-aineen hydrolyysissä esiintyvät inhibiittorit.
Kokeellisessa osiossa tehtiin pienen mittakaavan esikäsittelyjä puumateriaalille, jotta saatiin selville käsittelyssä syntyneet potentiaaliset inhibiittorit.
Tulosten perusteella valituilla inhibiittoreilla tehtiin lyhyen ja pitkän aikavälin hydrolyysikokeita laboratoriomittakaavassa.
Kokeiden perusteella merkittävimpinä inhibitioina voidaan pitää glukoosin ja ligniinin aiheuttamaa inhibitiota.
Näiden aineiden esiintymistä entsymaattisessa hydrolyysiliuoksessa olisi vähennettävä tai ehkäistävä.
Myös monosakkaridien ja fenolisten yhdisteiden aiheuttamaan inhibitioon on kiinnitettävä kokeiden perusteella erityistä huomiota.
Etanolia voidaan pitää merkittävänä inhibiittorina silloin, kun sen tavoitepitoisuudet ovat korkeat hydrolyysin aikana.
Furaaniyhdisteiden ja karboksyylihappojen aiheuttaman inhibition todettiin aiheuttavan ongelmia ainoastaan pitoisuuksien ollessa merkittäviä.
Tuloksista pääteltiin, että lignoselluloosaperäisen materiaalin hydrolyysissä esiintyvät ilmiöt ja mekanismit vaativat edelleen lisäselvityksiä.
ED:2014-09-21
INSSI record number: 49738
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