PhD Defense: Ancestral sequence reconstruction for protein engineering: improving cellulases for biomass hydrolysis

CIC nanoGUNE Seminars

Speaker

CFM Auditorium

When

2017/11/10
12:00

Place

nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian

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Developing strategies to improve the catalytic efficiency of enzymes for industrial applications is a long-standing goal in biotechnology. Although several methods based on sequence alteration are currently in place, improving enzymes in an effective and economically feasible manner is still a challenge. Here, we propose Ancestral Sequence Reconstruction (ASR) as a viable method for reconstructing enzymes with improved capabilities for biotechnological and industrial applications. This technique reconstructs enzymes from extinct organisms that lived in the harsh environments of ancient Earth, which are akin to some industrial settings. Here we “resurrect” three ancestral bacterial cellulases (endoglucanase, exoglucanase and beta-glucosidase) from the late Archean eon (~2800 Myr ago). These enzymes are able to hydrolyze cellulose with high efficiency in a broad range of temperature and pH conditions as well as using different cellulosic substrates. The ancestral cellulases show specific activity much higher than that of contemporary commercial cellulases; they also show a remarkable synergy in combination with other enzymes for lignocellulosic biomass degradation. Moreover, the endoglucanase also shows higher activities upon its integration into a bacterial cellulosome. Our results demonstrate ASR as a viable technique for enzyme design. **Supervisor** : R. Perez-Jimenez