Njoku, Stephen Ikechukwu1; Uellendahl, Hinrich2; Ahring, Birgitte Kiær3
1 Aalborg University Copenhagen, The Faculty of Humanities, Aalborg University, VBN2 Section for Sustainable Biotechnology, Copenhagen, The Faculty of Engineering and Science, Aalborg University, VBN3 Department of Chemistry and Bioscience, The Faculty of Engineering and Science, Aalborg University, VBN4 The Faculty of Engineering and Science (ENG), Aalborg University, VBN
The choice of a suitable pretreatment method and the adjustment of the pretreatment parameters for efﬁcient conversion of biomass are crucial for a successful bioreﬁnery concept. In this study, cocksfoot grass, a suitable lignocellulosic biomass with a potential for large-scale production was investigated for cellulosic ethanol production. The biomass raw materials were pretreated using wet explosion (WEx) at 25% dry matter concentration with addition of oxygen or dilute sulfuric acid. The enzymatic hydrolysis of cellulose was signiﬁcantly improved after pretreatment. The highest conversion into cellulose monomeric C6 sugars was achieved for WEx condition AC-E (180°C, 15 min, and 0.2% sulfuric acid). For that condition, the highest ethanol yield of 197 g/kg DM (97% of theoretical maximum value) was achieved for SSF process by Saccharomyces cerevisiae. However, the highest concentration of hemicellulose C5 sugars was found for WEx pretreatment condition O2-A (160°C, 15 min, and 6 bar O2) which means that the highest potential ethanol yield was found at this moderate pretreatment condition with oxygen added. Increasing the pretreatment temperature to 180–190°C with addition of oxygen or dilute sulfuric acid signiﬁcantly degrades the solubilized hemicellulose sugars and thus, achieved the highest formation of by-products.
Journal of the Society for Chemical Industry, 2013, Vol 1, Issue 2, p. 89-98