5. Conclusion
This work demonstrates that biological abatement facilitates
fermentation of sugars obtained from dilute acid pretreatment
of rice hulls. A specially selected microbe, C.
ligniaria NRRL30616, was used to metabolize undesirable
compounds which, if left untreated, can complicate microbial
conversion of sugars to the desired end product. In
ethanol fermentations, conversion of glucose in bioabated
hemicellulose hydrolyzates proceeded to completion, while
fermentations in unabated samples either stalled or failed to
completely utilize glucose. Increased utilization of xylose by
ethanologenic E. coli FBR5 and the xylose-utilizing yeast S.
cerevisiae YRH400 was also observed. Bioabatement was
associated with enhanced ethanol production in fermentations
of dilute acid-pretreated rice hulls and may facilitate
utilization of this feedstock, which presently has little
commercial use.
Acknowledgements
The authors thank Patricia O’Bryan for excellent technical
assistance and Rice Hull Specialty Products (Stuttgart, AR) for
the gift of ground rice hulls.