Production of ethanol from wet oxidised wheat straw by Thermoanaerobacter mathranii

The wet oxidation process (water, oxygen, elevated temperature, sodium carhonate) was investigated as a means of soluhilising hemicellulose from wheat straw. Sixteen diffcrcnt comhinations of oxygen pressure and sodium carhonate concentration were applied. The hemicellulose hydrolysates were evaluated with respect to total sugars, xylose, and 2-furfural produced. The concentration of sugars tended to he highest in hydrolysates produced at high oxygen pressures, whereas the concentration of 2-furfural was lowest in hydrolysates produced at low oxygen pressures and high carhonate concentrations, Fermentation of the hydrolysates was carried out using Thermoullaeronacter mathranii strain A3M I. No significant inhihitory effect was ohserved when the hydrolysates were fermented hy T. mathranii A3M I, However. the soluhilised hemicellulose was only partly available for fermentation hy the hacteria. Treatment with the commercial cnzyme Celluclast" or with acid hydrolysis improved the ethanol yield from the hydrolysates. Treatment with Pentopan Til Mono BG or Pulpzymeʹ" He, hoth endo-I ,4-fi-xylanases, had no effect neither had co-cultivation with the xylanase-produeing Dictyogiomlls B4.