ΠΜΣ Μικροβιακή ΒιοτεχνολογίαLibrary of the School of Science
Δημήτρης Χατζηνικολάου Επικ. Καθηγ. (Επιβλέπων), Αμαλία Καραγκούνη - Κύρτσου Καθηγ., Γεώργιος Διαλλινάς Αναπλ. Καθηγ.
Διερεύνηση της δυνατότητας αξιοποίησης του μύκητα Paecilomyces variotii στην παραγωγή αιθανόλης από λιγνινοκυτταρινούχα υποστρώματα με διεργασία ενός σταδίου.
Bioethanol is considered as the most promising renewable energy source for
fossil fuel replacement. The lignocellulosic biomass is an ideal raw material
to produce fuel ethanol due to its wide availability and its environmentally
sustainable production. The microbial production of ethanol from lignocellulose
requires four distinct steps of biological conversion: the production of
biomass- degrading enzymes (cellulases and hemicellulases), the hydrolysis of
the corresponding polysaccharides, and the fermentation of the resulting
monomeric sugars (pentoses and hexoses) to ethanol. The current methods for the
microbial conversion of lignocellulose to ethanol include a separate step
dedicated to the production of the saccharolytic enzymes and the degradation of
the substrate to simple sugars, before they can be utilized by an ethanologenic
microorganism, as most of the strains used today for such processes do not
possess the ability to degrade complex polysaccharides. The cost of the overall
process could be significantly reduced if the direct conversion of
lignocellulose to ethanol was possible. Such a process, called consolidated
bioprocessing (CBP) requires the use of a microorganism capable of adequately
performing all the necessary bioconversions.
In the present study, we examined the effect of a number of process parameters
on the production of ethanol from the filamentous fungus Paecilomyces variotii,
in order to evaluate its potential in consolidated bioprocessing applications.
Specifically, we attempted to find the optimum conditions for ethanol
production, as well as to evaluate the potential of the fungus in the
production of lignocellulose - degrading enzymes. The fungus is able to ferment
both glucose and xylose to ethanol with exceptionally high yields, close to the
theoretical maximum value. Moreover, it is able to grow on complex
lignocellulosic substrates as sole carbon source, while producing all the
necessary enzymes for the degradation of cellulose and hemicellulose. Our
results demonstrate that P. variotii possess all the necessary traits for
consolidated bioprocessing applications, and therefore the possibility of its
use in such processes is worthy of further investigation.
Bioethanol, Lignocellulose, Consolidated bioprocessing, Paecilomyces variotii, Fungi
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