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Ideal design of bioreactor can increase the productivity of bacterial cellulose synthesis. Many
method and design of bioreactor have previously investigated Watanabe et al, 1998. Some of those
methods are potentially applied in commercial and economical of bacterial cellulose production. In
dynamic media with agitation culture, high cellulose production needs high oxygen transfer rate means
big motor and energy is required. The inluenced of agitator coniguration to oxygen transfer rate have
been investigated Matsuoka et al., 1996. From those investigations it was concluded that stirred tank
reactor using gate with turbine impellers or maxblend agitator type are the best one Kouda et al., 1997.
Results and Discussions 4.1 Design and Engineering of Bioreactor
From the literature review, the reactor type suitable for bacterial cellulose production was chosen. It was
a Stirred Tank Reactor with gate and turbin-rushton agitator type. The dimension of the reactor is about
100 L volume and height 750 mm. All the size component of the reactor depends on this dimension.
The following igure 5 shows the design of the reactor. The bioreactor equipped with temperature control
of the culture media and rotation control of the agitator. A heater element is jacketed to the reactor.
Temperature can be varied from 30 to 120 °C and the sterilization methods up to 100 °C is done by this way.
The agitation speed can be varied from laminar to turbulent type of growth media.
4.2 Surface Modiication of Fibers
Surface modiication happens due to the growing of bacterial cellulose on the surface of the ibers by
Acetobacter xylinum. The pattern of growth cellulose can be seen on SEM observation which show that
bacterial cellulose more locculated on the surface of the long ibers NBKP than on short ibers LBKP.
In LBKP, bacterial cellulose distributed more evenly on the surface of the ibers. Uniform distribution is
Source : Sani Dahman, 2009
Figure 3. Bioreactor Types for Bacterial Cellulose Production
Source : Kouda et al., 1997
Figure 4. Agitator Coniguration for Bacterial Cellulose Production
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Fig. 5 Design of Bioreactor
Short Fibers Long Fibers
Separate Short and Long Fibers
ShortLong = 75 25 ShortLong = 50 50
ShortLong = 25 75 Mixed ShortLong Fibers
Figure 6. Surface Modiication of the Fibers for 1 Hour Incubation
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Short Fibers Long Fibers
Separate Short and Long Fibers
Mixed ShortLong Fibers Figure 7. Paper Sheets Evaluation
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more needed for papermaking than the locculated. The following igures 6 show the condition of
ibers surface each for short and long ibers alone and the combination of the twos. These combinations
needed because in papermaking there is always mixing of short and long ibers. The SEM picture was
taken for 1 hour incubation as the best time of surface modiication obtained from the experiments.
From the laboratory activity it was observed that the long ibers tend to agglomerate on the reactor
than the short one. This agglomeration disturbs the homogeneity of the stock when it used in papermaking.
Therefore the further investigation should be focus on
short ibers. This is in line with the development of paper industry when the using of long ibers reduces
and changes to short ibers.
4.3 Paper Sheets Evaluation
