IQUIBICEN   23947
INSTITUTO DE QUIMICA BIOLOGICA DE LA FACULTAD DE CIENCIAS EXACTAS Y NATURALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Producción de celulosomas artificiales para mejorar la degradación de lignocelulosa: un paso hacia energías limpias
Autor/es:
GOLDBAUM FA.; GOROJOVSKY N.; IGLESIAS RANDO MR.; CRAIG PO.
Reunión:
Congreso; Jornadas Exactas y el Agro; 2019
Resumen:
Lignocellulose is the most abundant renewable resource on the planet and it is an excellent substrate for the production of biofuels. Its enzymatic degradation generates sugars that upon fermentation produce bioethanol. For an economically viable production of biofuels it is essential to develop new methods to increase the activity and stability of the enzymes involved in this process. The cellulosomes of some anaerobic organisms represent the most efficient machinery for the degradation of lignocellulose. These multienzymatic complexes co-localize different cellulolytic enzymes and cellulose binding domains, increasing their degradation activity through enzymatic proximity and substrate targeting effects. However the biological production of artificial cellulosomes on an industrial scale has serious limitations. Our goal is to develop artificial cellulosomes using an oligomeric protein scaffold that is highly stable and highly expressed in bacteria for the co-localization of cellulases, hemicellulases, beta-glucosidases and cellulose binding domains. For the assembly of these multienzymatic particles we use a non-covalent coupling strategy through high affinity heterodimeric modules, cohesin and dockerin, complementary fused to the scaffold subunits and the target proteins, respectively. In this work, we focus on the structural and functional characterization of a monospecific cellulosome composed by an endoglucanase. The polymeric display of the endoglucanase on the structural scaffold produce a significant increment in the degradation rate of cellulose compared to the free enzyme. This phenomenon seems to be related to an increase in the binding strength of the multienzymatic complex to the substrate due to an avidity effect. Addition of a cellulose binding domain to this cellulosome does not improve the degradation rate of the substrate, probably due to a redundant targeting effect. A significant increment in the thermal stability of the enzyme coupled to the scaffold compared to the free enzyme was also observed. We are making progress in the simultaneous coupling of a variety of enzymes to the scaffold. It is expected that this technology would be valuable to improve lignocellulose degradation.