Properties of Bacterial Cellulose

The physical properties of cellulose synthesized by bacteria depend on several processing parameters such as  

No BC sheet preparing method Young s modulus (GPa) Tensile strength(MPa) Bacterial strain used References 

2 BC hydrogel treated with NaOH and NaOCl aqueous solution followed by hot pressing 30 AJ12368 [29] 

3 Compression molding of oven-dried BC with applied pressme of 100 Mpa 10.6 182.5 unknown [24] 

4 Vacuiun dried at 80 C 6.6 122 Acetobacter Xyhniun from rotten grapes [30] 

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The strengths of the resulting dried sheets were tested by applying mechanical compression forces to determine the relative effects of the bacterial strains. As shown (Table 2), there were no significant differences between the textures of all bacterial cellulose strength levels derived from the three strains. Both coconut and pineapple juices yielded the same strength rating. The mechanical properties of bacterial cellulose, both air-dried and hot-pressed... 

Backdahl, H., Helenius, G., Bodin, A., Nannmark, U., Johansson, B. R., Risberg, B., and Gatenholm, P. (2006). Mechanical properties of bacterial cellulose and interactions with smooth muscle cells,... 

Zhang, S., and Luo, J. (2011). Preparation and properties of bacterial cellulose/alginate blend bio-fibers,/. Eng. Fiber. Fabr., 6,69-72. 

Nge, T. T., Nogi, M., Yano, H., and Sugiyama, J. (2010). Microstructure and mechanical properties of bacterial cellulose/chitosan porous scaffold, QslMSS f 349-363. 

Dammstrdm, S., Salmdn, L., Gatenholm, P. The effect of moisture on the dynamical mechanical properties of bacterial cellulose/glucuronoxylan nano composites. Polymer 46, 10364-10371 (2005)... 

Watanabe, K., Yamanaka, S. Effects of oxygen tension in the gaseous phase on production and physical properties of bacterial cellulose formed under static culture conditions. Biosci. Biotechnol. Biochem. 59(1), 65-68 (1995)... 

Watanabe, K., Tabuchi, M., Morinaga, Y., Yoshinaga, F. Structural features and properties of bacterial cellulose produced in agitated-culture. Cellulose 5(3), 187-200 (1998)... 

Scionti, G., 2010. Mechanical Properties of Bacterial Cellulose Implants. Chalmers Tech. University, Goteborg. 

The specific properties of bacterial cellulose make it interesting for important applications, such as a nutritional component (additive of low caloric contents, stabilizer, texture modifier, nata de coco), a pharmacological agent (temporary dressing, excipient, cosmetics, drug carriers), as well in telecommunications and papermaking, as summarized in Table 17.2. 

The crystallinity of bacterial cellulose has an influence on its mechanical properties. In 1990, Brown et al. [21] showed that under an intense magnetic field (1.8 T), their G. xylinus strain produced cellulose with no crystalline regions. One characteristic of that cellulose was a lower tensile strength, compared to that of a sample obtained without magnetic field. Therefore, an increase in the amount of crystalline phase can lead to an improvement of the mechanical properties of bacterial cellulose membranes. 

Bacterial cellulose-modified sisal and hemp fibres have also been used to produce unidirectional natural fibre reinforced CAB and polylactide (PLLA) model composites [9]. The mechanical properties of bacterial cellulose-coated sisal fibre reinforced polymers showed significant improvements over neat polymers (Table 6.8). The tensile strength and modulus for sisal/PLLA composites improved by as much as 68 and 49%, respectively. However, improvements were... 

Table 6.8 Mechanical properties of bacterial cellulose modified hemp and sisal fibres reinforced CAB and PLLA composites ...

Bodin A, Backdahl H, Fink L et al (2007a) Influence of cultivation conditions on mechanical and morphological properties of bacterial cellulose tubes. Biotechnol Bioeng 97 425-434 Bodin A, Concaro S, Brittberg M et al (2007b) Bacterial cellulose as a potential meniscus implant. 

Keshk, S.M.A.S., 2006. Physical properties of bacterial cellulose sheets produced in presence of lignosulfonate. Enzyme and Microbial Technology 40, 9—12. 

Krystynowicz A., Czaja W., Wiktorowska-Jezierska A., Gongalves-Mi kiewicz M., Turkiewicz M., and Bielecki S. 2002. Factors affecting the yield and properties of bacterial cellulose. J Ind Microbiol Biotechnol 29 189-195. 

M. Ul-Islam, T. Khan, and J.K. Park, Water holding and release properties of bacterial cellulose obtained by in situ and ex situ modification, Carbohyd. Polym., 88, 596-603,2012. 

Another purpose of adding chemicals to the culture medium is the chemical modification of the structural and physical properties of bacterial cellulose, allowing the preparation of composites directly during biosynthesis and broadening the applications of cellulose [18], as will be discussed latter. 

Tailor-Designing Bacterial Cellulose 4.3.1 Modifying the Properties of Bacterial Cellulose... 

Determining techniques to alter the properties of bacterial cellulose could provide methods to target and achieve specific characteristics. The abihty to tailor-design bacterial cellulose with desirable traits would increase the potential for this material to be used as a reinforcement material for composites. 

There has also been a recent paper that reported the achievement of individual fibers of bacterial cellulose. Kose et al. [144] used an aqueous counter colhsion method that caused a separation of the interwoven mesh of fibers in the pellicle into individual fibers, dispersed in water (Figure 4.8). They completed different repetitions of this treatment and found that the width and length of the fibers changed with the number of treatments, and that cellulose was converted to 1, but that the cellulose retained its high crystallinity. This method provides further indication that the treatment of the cellulose prior to its inclusion in a composite can result in different properties, with a technique that can target not only specific properties of bacterial cellulose, but can achieve individual fibers for further use. 

Although the chemical structures of plant and bacterial cellulose are identical, the physical stmcture of bacterial cellulose is unique, being composed of ultrafine fibers that form an ultrafine network. The mechanical properties of bacterial cellulose are also unique. In this chapter, the mechanism of acetic acid bacteria cellulose biosynthesis, and its biological functions, properties, and industrial applications, are described. 

Considering the unique properties of bacterial cellulose, many aspects regarding its industrial application are promising and show great potential. However, economic feasibility is primarily dependent on its production cost. Many investigations and trials in both application and production systems are needed before large-scale production becomes a reality. 

Watanabe K, Eto Y, Takano S, Nakamori S, Shibai H, Yamanaka S (1993) A new bacterial cellulose substrate for mammalian cell culture. Cytotechnology 13 107-114 Watanabe K, Tabuchi M, Morinaga Y, Yoshinaga F (1998) Structural features and properties of bacterial cellulose produced in agitation culture. Cellulose 5 187-200 Whitney JC, Hay ID, Li C, Eckford PDW, Robinson H, Amaya MF, Wood LF, Ohman DE, Bear CE, Rehm BH, Howell PL (2011) Structural basis for alginate secretion across the bacterial outer membrane. Proc Natl Acad Sci USA 108 13083-13088... 

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