Team:Berlin/Project/property
5. Properties of Enzymatic Flagellulose
Properties of Cellulose:
A bacterially synthesized cellulose fiber shows exceptional material properties such as high
chemical and thermal stability, biocompatibility and bioinertness and high mechanical stability.
The diameter of a bacterial cellulose fiber is about 40-60 nm, which corresponds to one-
hundredth of the diameter of a plant fiber. The modulus of elasticity is about 134 GPa, which can
be compared with the one of cast iron (grey cast iron: E = 90 - 140 GPa). A single fiber shows
the tensile strength of 2 GPa, this is comparable with some stainless steel types like AK steel
(AK Steel 17-7 PH: Rm = 1,3 - 1,5 GPa).[6],[7],[8],[9]
The study of the iGEM Team of the Imperial College London (2014) advises a maximum
working shear stress of 7.5 MPa.[10]
The nano structured system shows a large specific surface (60-100 m2/g), this is responsible for
the possibility of intense interactions.[6]
One example is the link of cellulose binding domains (CBDs) to the cellulose matrix by
hydropbobic interactions. Genetic engineering is our solution for the attachment of the Flagellas
on our surface material. This means an effective immobilization of CBD-flagellin fusion proteins
on the cellulose matrix without the need for covalent cross linking. The results of Kauffmann et
al. (2000) show that the CBD causes no activity loss of the attached protein. In addition
immobilization often results in a higher stability of the protein.[11]
Life-time of the product:
The estimated half-life of cellulose itself at 25° C is about 5-8 million years.
It can be degraded aerobically and anaerobically. The degradation is catalyzed by a range of
enzymes in cellulolytic microorganisms. Three types of enzymes are involved in the degradation
process: endoglucanases, cellobiohydrolases, and β-glucosidases.
The known enzymes responsible for cellulose degradation, as well as the cleavage sites, are
shown in table 1.
Currently, we are still researching some other properties. We are focusing on following
questions:
How good are the links between the flagella and cellulose, and the flagella and enzymes?
How does this fact affect the life time of our product?
Synthetic biology is of high interest for maker and do-it-yourself biology community. DIYbio
spaces and groups are being formed continuously all over the globe (diybio.org).
Often people that are involved in diybio are able to come up with clever solutions to manufacture
biomaterials as well as bio lab equipment improvising. The production of cellulose in a diybio
setting has been demonstrated in various projects like in art projects such as “Xylinum Cones”
from Berlin based designer Jannis Huelsen
or a speculative approach by iGEM Berlin member and designer Valerian Blos in his works about “Restriction as design and design as restriction” . This indicates that, first, there is a communal interest in cellulose as a biomaterial and second that cellulose production does not have to occur in a laboratory setting. For this, the Flagellulose may be further developed outside of the academic setting. Especially so, as the Biobricks produced will be openly
accessible through the iGEM registry.
[6] F. Wesarg: Herstellung funktioneller Hybride auf Basis von bakteriell synthetisierter Nanocellulose
(Doctoral dissertation, Jena, Friedrich-Schiller-Universität Jena, Diss., 2013).
[7] D. Klemm, B. Heublein, H.-P. Fink and A. Bohn: Cellulose: Fascinating Biopolymer and Sustainable Raw
Material, Angew. Chem. Int. Ed. 44 [22] (2005), 3358-3393.
[8] G. Guhados, W. Wan and J.L. Hutter: Measurement of the elastic modulus of single bacterial cellulose
fibers using atomic force microscopy, Langmuir 21 [14] (2005), 6642-6646.
[9] H. Yano, J. Sugiyama, A.N. Nakagaito, M. Nogi, T. Matsuura, M. Hikita and K. Handa: Optically
Transparent Composites Reinforced with Networks of Bacterial Nanofibers, Adv. Mater. 17 [2] (2005),
153-155.
[10] iGEM Team of the Imperial College London (2014).
https://2014.igem.org/Team:Imperial/Mechanical_Testing
[11] C. Kauffmann, O. Shoseyov, E. Shpigel, E. A. Bayer, R. Lamed, Y. Shoham and R. T. Mandelbaum: Novel
methodology for enzymatic removal of atrazine from water by CBD-fusion protein immobilized on
cellulose. Environmental science & technology 34.7 (2000): 1292-1296.
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