Engineered Microbial Consortium for the Efficient Conversion of Biomass to Biofuels Page: 69

                                
carbon source that does not yield loose monosaccharides that could support the growth of the wild
type ZM4.
Fresh batches of cultures were grown on cellulose filter paper under the same conditions
as described above. The use of cellulose filter paper was also to determine the amount of reducing
sugars released according to the methods of Xiao et al. [197] and to see whether there would be
any synergy between wild type ZM4 and C. cellulolyticum in the co-culture using an alternative
source of cellulose. Ethanol production was quantified as described previously. Ethanol was
originally detected in the wild type ZM4 cultures using microcrystalline cellulose as the substrate
and the switch to cellulose filter paper was in part to establish if free contaminating
monosaccharides exist in the medium with microcrystalline cellulose. Figure 5.5 below is the
standard curve of reducing sugar activity for estimation of the amount of reducing sugars released
by the wild type ZM4, C. cellulolyticum and ZM4 + Clostridium.
0.7
0.6 -
0.1-
0.0      0.2     0.4      0.6     0.8 10          1.2
mg/ml of glucose
Figure 5.5: Standard curve of reducing sugar activity.

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