Presence of cellulose II in the particulate material produced
by the F2-2 culture. To examine whether the F2-2 culture produced
cellulose, the chemical nature of the particulate material in
the static culture was investigated. The sample was prepared from
the static culture because the amount of particulate material was
greater than that found in the agitated culture. Solid-state 13C
NMR spectra were obtained with proton-carbon CP-MAS. The
13C CP-MAS NMR spectra of alkali-insoluble materials from
wild-type (Fig. 2Aa) and F2-2(pSA-CMCax/k) (Fig. 2Ab) pellicles
were found to be very similar to previously published spectra of
cellulose I (7). In contrast, the C6 signal in the spectrum of the
alkali-insoluble material obtained from the F2-2 culture was
shifted upfield (Fig. 2Ac). Furthermore, the C4 signal (Fig. 2Ac,
dagger) was also shifted slightly upfield, and the C1 signal became
a doublet at 104.5 and 105.6 ppm. The spectrum of the particulate
material obtained from the F2-2 culture was similar to that of
NaOH-treated Avicel (see Materials and Methods), which represents
typical cellulose II (Fig. 2Ad). These observations (Fig. 2A)
suggest that the particulate material from the F2-2 culture contained
cellulose with a crystalline structure similar to that of cellulose
II.