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CELLULOSE DEGRADING
- C. hutchinsonii is capable of completely degrading crystalline cellulose
- almost 70 % of CMCase (carboxymethyl cellulose) activities were in the periplasm of C. hutchinsonii
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the cellulose degradation system in C. hutchinsonii may be different from those of previously studied microorganisms; thus, carbohydrate binding and transport is interesting.
Many researchers believe this bacterium may have a unique cellulose-degrading mechanism which is different from either the free cellulase system or the cellulosome complex [Wilson 2008, Xie et al. 2007].
- "Most putative ß-1,4-endoglucanases of C. hutchinsonii are presumably extracellular or outer membrane associated... However, even with all the theoretical expectations, the exact cellulose degrading mechanism is still unclear."
- Direct adhesion is needed for C. hutchinsonii to hydrolyze cellulose, but no obvious encoded protein has been found relating to adhesion [Xie et al. 2007].
MANIPULATION
- Insertion of plasmids directly to C. hutchinsonii has been reported by Xu et al. (2011). McBride and Baker (1996) have reported transformation of C hutchinsonii by conjugation.
CULTURE
Mineral salt related media are suitable for isolation of C. hutchinsonii. Colonies on filter paper are large, spreading and bright yellow, the center soon becoming translucent and somewhat slimy.
Colonies on glucose mineral agar are bright yellow, more or less compact to slightly spreading, with an entire or wavy edge and moderately raised to flat [Larkin 1989].
In liquid media with cellulose or glucose, slime may be produced, making the culture viscous and harvesting difficult. Diethyleneglycol is reported to be a good solvent for slime isolation [Verma & Martin 1967]. C. hutchinsonii can use peptone, yeast extract, several amino acids, nitrate and ammonium as nitrogen source. Cellulose [McBride & Baker 1996, Walker & Warren 1938], CMC [Louime et al. 2006], cellodextrin [Zhu et al. 2010], cellobiose, or glucose can be used as sole carbon source [Larkin 1989].
The mineral medium used for C. hutchinsonii culture was modified from
Dubos Salts Medium [Atlas 2010]. Cells were cultured on DSM3T agar plates
(Appendix I) supplemented with carbon sources: 0.2 g glucose, 0.2 g cellobiose or
0.2 g filter paper strip. The plates were incubated at 30 ºC and checked daily. For
liquid cultures, cells were cultured in 100 ml of DSM3T medium (Appendix I)
incubated at 28 ºC, shaking at 100 rpm for 14 days supplemented with carbon source:
0.5 g filter paper, 0.5 g glucose or 1.0 g cellobiose.
Paper on Plasmids in C. hutchinsonii