Ethanol production from rape straw by a two-stage pretreatment under mild conditions
- 348 Downloads
The growing interest on rape oil as raw material for biodiesel production has resulted in an increasing availability of rape straw, an agricultural residue that is an attractive renewable source for the production of second-generation bioethanol. Pretreatment is one of the key steps in such a conversion process. In this work, a sequential two-stage pretreatment with dilute sulfuric acid (130 °C, 60 min, 2 % w/v H2SO4) followed by H2O2 (1–5 % w/v) in alkaline medium (NaOH) at low temperature (60, 90 °C) and at different pretreatment times (30–90 min) was investigated. The first-acid stage allows the solubilisation of hemicellulose fraction into fermentable sugars. The second-alkaline peroxide stage allows the delignification of the solid material whilst the cellulose remaining in rape straw turned highly digestible by cellulases. Simultaneous saccharification and fermentation with 15 % (w/v) delignified substrate at 90 °C, 5 % H2O2 for 60 min, led to a maximum ethanol production of 53 g/L and a yield of 85 % of the theoretical.
KeywordsRape straw Sequential pretreatment Hydrogen peroxide Delignification Ethanol
J.C. López-Linares gratefully acknowledges the research grant received from University of Jaén (Plan de Apoyo).
- 1.Zhang B (2013) Pretreatment technologies for production of lignocellulosic biofuels. Biomass Conv Bioref 329–345Google Scholar
- 4.FAOSTAT (2014) http://faostat.fao.org/. Accessed 01 Apr 2014
- 5.Arvaniti E (2012) Ethanol production from rape straw: part of an oilseed rape biorefinery. Ph.D. Dissertation, Technical University of DenmarkGoogle Scholar
- 6.Gupta A (2014) Use of cellulose for sustainable bioenergy production. Int J Appl Eng Res 9(2):239–240Google Scholar
- 15.de Souza CJA, Costa DA, Rodrigues MQRB, dos Santos AF, Lopes MR, Abrantes ABP, dos Santos Costa P, Silveira WB, Passos FML, Fietto LG (2012) The influence of presaccharification, fermentation temperature and yeast strain on ethanol production from sugarcane bagasse. Bioresour Technol 109:63–69CrossRefGoogle Scholar
- 16.Lima MA, Lavorente GB, da Silva HKP, Bragatto J, Rezende CA, Bernardinelli OD, de Azevedo ER, Gomez LD, McQueen-Mason S, Labate CA, Polikarpov I (2013) Effects of pretreatment on morphology, chemical composition and enzymatic digestibility of eucalyptus bark: a potentially valuable source of fermentable sugars for biofuel production—part 1. Biotechnol Biofuels 6:75CrossRefGoogle Scholar
- 20.National Renewable Energy Laboratory (NREL). Chemical analysis and testing laboratory analytical procedures. http://www1.eere.energy.gov/biomass/analytical_procedures.html. Accessed 14 Jan 2015
- 21.Singleton VL, Rossi SA (1965) Colorimetric of total phenolics with phosphomolibic-phosphotungstic acid reagents. J Enol Vitic 16:144–158Google Scholar