Synthesis of cellulose by <i>Acetobacter xylinum</i>. 2. Preparation of freeze-dried cells capable of polymerizing glucose to cellulose

Hestrin, S.; Schramm, Michael

doi:10.1042/bj0580345

Cited by 1,091 publications

(524 citation statements)

References 10 publications

(14 reference statements)

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“…Bacterial cellulose (BC) was produced by the bacterial strain Acetobacter aceti (AJ-12368), a cellulose producing species closely related to G. xylinus, in the Schramm-Hestrin (SH) medium (Hestrin and Schramm 1954). An aqueous suspension of BC nanofibrils was obtained by homogenizing the BC pellicles with a OBH Nordica blender.…”

Section: Methodsmentioning

confidence: 99%

Topochemical acetylation of cellulose nanopaper structures for biocomposites: mechanisms for reduced water vapour sorption

et al. 2014

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Moisture sorption decreases dimensional stability and mechanical properties of polymer matrix biocomposites based on plant fibers. Cellulose nanofiber reinforcement may offer advantages in this respect. Here, wood-based nanofibrillated cellulose (NFC) and bacterial cellulose (BC) nanopaper structures, with different specific surface area (SSA), ranging from 0.03 to 173.3 m 2 /g, were topochemically acetylated and characterized by ATR-FTIR, XRD, solid-state CP/MAS 13 C-NMR and moisture sorption studies. Polymer matrix nanocomposites based on NFC were also prepared as demonstrators. The surface degree of substitution (surface-DS) of the acetylated cellulose nanofibers is a key parameter, which increased with increasing SSA. Successful topochemical acetylation was confirmed and significantly reduced the moisture sorption in nanopaper structures, especially at RH = 53 %. BC nanopaper sorbed less moisture than the NFC counterpart, and mechanisms are discussed. Topochemical NFC nanopaper acetylation can be used to prepare moisturestable nanocellulose biocomposites.

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Section: Methodsmentioning

confidence: 99%

Topochemical acetylation of cellulose nanopaper structures for biocomposites: mechanisms for reduced water vapour sorption

et al. 2014

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“…13 C BC was prepared by stationary cultivation of Acetobacter xylinum in Hestrin-Schramm medium 9 supplemented with 13 C 6 -glucose ( 13 C499%), which was purchased from Cambridge Isotope Laboratories (Andover, MA, USA). The pellicles were cut into pieces with a food cutter.…”

Section: Materials and Methods Materialsmentioning

confidence: 99%

Statistical approach for solid-state NMR spectra of cellulose derived from a series of variable parameters

Okushita

Komatsu

Chikayama

et al. 2012

Polym J

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Principle component analysis (PCA) was used to extract components from the solid-state nuclear magnetic resonance (NMR) spectra of bacterial cellulose (BC). Polymers such as cellulose have several domain structures, and their structure and dynamics are reflected in the variety of solid-state spectra derived from different parameters. The complexity of the obtained spectra makes the analysis of spectra from relaxation measurements difficult. Multivariate analysis, such as PCA, has been suggested as an option to improve NMR spectral analyses. In this study, we attempted to extract peak components from cross polarization (CP) experiment data from the variable contact time spectra of BC by using PCA. The extracted peaks were annotated according to previous reports, and the existence of crystalline Ia was clearly recognized. The important components of the BC structure (that is, crystalline Ia, amorphous form and mobility) were separated in the PCA-loading plot and CP curve.

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“…Methylobacterium organophilum NCIB 11278 was grown a t 30°C either in an ammonium mineral salts medium containing 0.5% of methanol [5], or in the medium of Hestrin and Schramm [6]. Nostoc muscorum B-1452-12b (Pflanzenphysiologisches Institut, Universitit Gottingen, FRG) was grown under continuous illumination in 5-1 bottles according to Brandt et al [7] in the medium of Kratz and Myers [8].…”

Section: Bacteria and Culture Conditionsmentioning

confidence: 99%

Prokaryotic triterpenoids

Bisseret¹,

Zundel²,

Rohmer³

1985

European Journal of Biochemistry

105

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2P-Methylhopanoids, a new series of triterpenoids was identified from two prokaryotes. 2P-Methyldiplopterol was isolated from the methylotrophic bacterium Methylobacterium organophilum, and three different 2B-methylbacteriohopanepolyols from the cyanobacterium Nostoc muscorum. The structures of these compounds was deduced by direct comparison with 2P-methyldiplopterol synthesized from 22-hydroxyhopan-3-one.Among the prokaryotic triterpenoids, the hopanoids possessing an extra methyl group at C-3P are easily detected for instance by gas-liquid chromatography or gas-liquid chromatography coupled to mass spectrometry of suitable derivatives [l]. The presence of the extra methyl group was clearly indicated by mass spectrometry by the characteristic ion at m/z = 205 (instead of m/z = 191 in the mass spectra of normal hopanoids) resulting from the ring C fragmentation [2]. Another series of methylhopanoids has been detected by us a few years ago in the cyanobacterium Nostoc muscorum [3, 41, but their structures remained unresolved. This paper now describes one of the major hopanoids, 2P-methyldiplopterol, from the methylotroph Methylobacterium organophilum, as well as various 2~-methylbacteriohopanepolyols (and their non-methylated homologues) from the cyanobacterium Nostoc muscorum, the side-chain structures of which are described for the first time. MATERIALS AND METHODS Bacteria and culture conditionsMethylobacterium organophilum NCIB 11278 was grown a t 30°C either in an ammonium mineral salts medium containing 0.5% of methanol [5], or in the medium of Hestrin and Schramm [6]. Nostoc muscorum B-1452-12b (Pflanzenphysiologisches Institut, Universitit Gottingen, FRG) was grown under continuous illumination in 5-1 bottles according to Brandt et al. [7] in the medium of Kratz and Myers [8]. The cells were harvested in the late logarithmic phase by centrifugation and freeze-dried. ISOLATION OF HOPANOIDSAll analytical procedures have been previously described [4,91. Correspondence to M. Rohmer, Ecole Nationale Suptrieure de Chiinie dc Mulhouse, 3 Rue Alfred-Werner, F-68093 Mulhouse Cedex, FranceAbbreviations. TLC, thin-layer chromatography; GLC, gas-liquid chromatography; NMR, nuclear magnetic resonance; MS, mass spectrometry. 2fi-Methyldiplopterol from M. organophilumThe CHC13/CH30H (2 : 1, v/v) extract of freeze-dried cells was acetylated [4] and, after removal of the excess of reagents under vacuum, separated by flash chromatography [lo] using cyclohexane/EtOAc (3 : 7, v/v) as eluent [l 11. The fractions containing diplopterol and/or 2~-methyldiplopterol were combined and further purified by TLC using CH2C12 as eluent and giving pure diplopterol and/or 2/3-methyldiplopterol (RF = 0.28). Pure 2P-methyldiplopterol isolated from cells grown on the Hestrin and Schramm medium was recrystallized from CH2C1,/CH,0H. M.p. Nostoc muscorum hopanoidsThe CHC13/CH30H extract of the freeze-dried cells (43 g) was hydrolyzed during 1 h by refluxing with a 6% solution of KOH in CH30H (30 mi). After addition of water (60 ml) the h...

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Synthesis of cellulose by Acetobacter xylinum. 2. Preparation of freeze-dried cells capable of polymerizing glucose to cellulose

Cited by 1,091 publications

References 10 publications

Topochemical acetylation of cellulose nanopaper structures for biocomposites: mechanisms for reduced water vapour sorption

Topochemical acetylation of cellulose nanopaper structures for biocomposites: mechanisms for reduced water vapour sorption

Statistical approach for solid-state NMR spectra of cellulose derived from a series of variable parameters

Prokaryotic triterpenoids

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