Bacterial microcrystalline cellulose

Cel9A is also of interest because it possesses very high activity on bacterial microcrystalline cellulose (BMCC) and an unusual synergistic activity in cellulase mixtures. It is unique in that it shows synergism with endocellulases and both types of exocellulases (20,21). It also retains more than 70% of its activity from pH 4.7 to 10.1. 

The role of CBMs may not be entirely passive, although thermodynamics ensure that any interaction has to be stoichiometric rather than catalytic. An isolated CBM 2a, originally from a Cellulomonas fimi endoglucanase, formed the usual (3-sandwich, but, in solution, when unconstrained by an attached catalytic domain, dimerised." This CBM liberated small particles from cotton linters but not bacterial microcrystalline cellulose the same behaviour was shown by the holoenzyme which had been inactivated with the appropriate Withers inactivator." " However, another CBM 2a, from Cellvibrio japonicus, was rigorously shown to act only by increasing substrate proximity." ... 

FIGURE 4 J Qualitative comparison of mechanistic model predictions (top row, from Griggs et al. (2012b)) with experimental results (bottom row, from Srisodsuk et al. (1998)) for the changing DP distribution of cellulose during enzymatic hydrolysis by EG, and CBH,. The left column compares resnlts for bacterial microcrystalline cellulose (BMCC) with a relatively low initial DP, and the right column compares results for cotton linter with a relatively high initial DP. For a color version, see the color plate section.)... 

Srisodsuk, M Lehtio, JML Msrgolles-Clark, E Reinikainen, T Teeri, TT. Trichoderma reesei cellobiohydrolase I with an endoglucanase cellulose-binding domain action on bacterial microcrystalline cellulose. Journal of Bacteriology, 1997, 57, 49-57. 

MC, microcrystalline cellulose SSP, spruce sulphite pulp CL, cotton Unters BC, bacterial cellulose DSP, dissolving pulp. 

Fig. 7.3 Transmission electron micrographs from dilute suspension of cellulose nanocrystals from (a) ramie (Habibi et al. 2008), (b) bacterial (Grunnert and Winter 2002), (c) sisal (Garcia de Rodriguez et al. 2006), (d) microcrystalline cellulose (Kvien et al. 2005), (e) sugar beet pulp...

The second main area of application for cellulose-based polymers is the encapsulation of active small molecules for drug delivery [40,48]. As briefly mentioned above, different celluloses are differently suited for this purpose. Generally, microcrystalline cellulose is the preferred material for this kind of application [63]. As a matter of fact, most applications in this field exploit bacterial cellulose. 

More recently, cellulose fibres have been investigated as potential precursors for self-reinforced polymer composites, as well summarised in a review by Eichhom et al. [191]. Numerous authors have reported the use of cellulose fibres from various sources, including wood pulp fibres [192, 193], filter and Kraft paper [194-197], microcrystalline cellulose fibres [198-202], sisal fibres [203, 204], ramie fibres [205], cotton fibres [206], regenerated cellulose (Lyocell) and cellulose fibres spun from an anisotropic phosphoric acid solution (Bocell) [207], and fibres from bacterial cellulose [208]. Two main technologies have been presented to produce these so-called self-reinforced cellulose or all-cellulose composites, and these are, first, the conventional impregnation of cellulose matrix into cellulose fibres and, second, a novel selective dissolution method in which the cellulose fibre surfaces are partially dissolved to form a matrix phase that bonds fibres together. 

MCQ microcrystalline cellulose DMF, dimethylformamide DMA, dimethylacetamide LiCL, lithium chloride BC, bacterial cellulose. ... 

Bacterial Cellulose. Development of a new strain of Acetobacter may lead to economical production of another novel ceUulose. CeUulon fiber has a very fine fiber diameter and therefore a much larger surface area, which makes it physicaUy distinct from wood ceUulose. Its physical properties mote closely resemble those of the microcrystalline ceUuloses thus it feels smooth ia the mouth, has a high water-binding capacity, and provides viscous aqueous dispersions at low concentration. It iateracts synergisticaUy with xanthan and CMC for enhanced viscosity and stabUity. 

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