Background:
There is currently considerable interest in developing renewable sources ofenergy. One strategy is the biological conversion of plant biomass to liquidtransportation fuel. Several technical hurdles impinge upon the economicfeasibility of this strategy, including the development of energy cropsamenable to facile deconstruction. Reliable assays to characterize feedstockquality are needed to measure the effects of pre-treatment and processingand of the plant and microbial genetic diversity that influence bioconversionefficiency.
Results:
We used the anaerobic bacterium Clostridium phytofermentans to develop arobust assay for biomass digestibility and conversion to biofuels. The assayutilizes the ability of the microbe to convert biomass directly into ethanol withlittle or no pre-treatment. Plant samples were added to an anaerobic minimalmedium and inoculated with C. phytofermentans, incubated for 3 days, afterwhich the culture supernatant was analyzed for ethanol concentration. Theassay detected significant differences in the supernatant ethanol from wildtypesorghum compared with brown midrib sorghum mutants previouslyshown to be highly digestible. Compositional analysis of the biomass beforeand after inoculation suggested that differences in xylan metabolism werepartly responsible for the differences in ethanol yields. Additionally, wecharacterized the natural genetic variation for conversion efficiency inBrachypodium distachyon and shrub willow (Salix spp.).
Conclusion:
Our results agree with those from previous studies of lignin mutants usingenzymatic saccharification-based approaches. However, the use of C.phytofermentans takes into consideration specific organismal interactions,which will be crucial for simultaneous saccharification fermentation orconsolidated bioprocessing. The ability to detect such phenotypic variationfacilitates the genetic analysis of mechanisms underlying plant feedstockquality.Source:
http://www.biotechnologyforbiofuels.com/rss/