Sunday, May 3, 2009
3-41
Bioethanol Production from Plasma Assisted Pretreatment of Wheat Straw Fermenting C5 and C6 sugars
Nadja Schultz, Zsófia Kádár, Frank Leipold, Annette Eva Jensen, Tomas Fernqvist, and Anne Belinda Thomsen. Biosystems Division, Risř National Laboratory for Sustainable Energy, Technical University of Denmark – DTU, Frederiksborgvej 399, Roskilde, Denmark
With the aim to develop progressive pretreatment technologies, the effect of O3 generated in an atmospheric pressure low temperature air plasma, for degradation of lignin was investigated. It was shown that this process can be described via an “instant analysis” correlating the amount of O3 consumed, with the amount of lignin degraded and the sugars developed in the sample. Lignin was degraded up to 95% but cellulose was found to remain unaffected for more than 7 hours pretreatment. This analysis allows to produce specifically either pretreated biomass with a very low amount of lignin (1%) or pretreated biomass that consists of a compromise between degraded lignin, fermentation inhibitors and the maximal amount of fermentable sugars for yeast. We investigated the potential of Pichia stipidis (ATCC 58785 and ATCC 58376) as a natural strain to ferment C5 and C6 sugars to bioethanol.It was found that the maximal amount of fermentable sugars was produced after 1 hour pretreatment and estimated by enzymatic hydrolysis (~25g 100g-1 cellulose, 12 g 100g-1 xylose) with respect to the dry mass. The O3 consumption was 0.2 g O3 per g wheat straw (1 mm, 50% DM). The optimal air flow rates were 0.6 L min-1 with the mini reactor (ø 7 cm) or 12 L min-1 with the multi-layer reactor (ø 30 cm) with an O3 concentration of 1 %.