Bioethanol from Dried Household Food Waste Applying Non-isothermal Simultaneous Saccharification and Fermentation at High Substrate Concentration
- 227 Downloads
Household food waste (HFW) a complex biomass containing soluble sugars, lipids, proteins, cellulose, was used for bioethanol production at high substrate concentration and low enzyme loadings. HFW was subjected to microwave digestion (121 °C, 15 min) at 20 % (w/v) substrate concentration in the presence or absence of dilute sulfuric acid. The whole slurry was hydrolyzed and simultaneously saccharified and fermented using 5 and 10 FPU/g dry HFW. Enzymatic hydrolysis resulted in glucose yields in the range of 44–47 % of the theoretical (based on potential glucose content in the HFW) for both enzyme loadings tested, indicating that enzyme loadings lower than 10 FPU/g HFW could be used. During SSF tests the highest ethanol production (23.12 g/L) was obtained from the pretreated in the presence of dilute sulfuric acid HFW at 10 FPU/g HFW. In an attempt to protect the soluble fraction from possible decomposition and increase ethanol concentration, hot water treatment and higher substrate concentrations were examined. At optimal pretreatment conditions (100 °C, 60 min), glucose yields of 54.69 and 58.39 % (of the theoretical based on potential glucose content in the HFW) were achieved at 30 and 50 % w/v substrate concentration, respectively, which corresponds to an ethanol production of 17.44 and 31.03 g/L, respectively. In order to overcome the technical difficulties due to high initial viscosity of the material, when operating hydrolysis and fermentation at high initial substrate concentrations, a non-isothermal simultaneous saccharification and fermentation process operating in fed-batch mode was applied at 40 % (w/v) final substrate concentration, resulting in 42.66 g/L (or 107 g/kg HFW) ethanol production.
KeywordsBioethanol Household food waste High solids Fed batch non-isothermal simultaneous saccharification and fermentation
This work is based on the research that was carried out in the framework of a LIFE + project entitled: «Development and demonstration of an innovative method of converting waste into bioethanol» Waste2Bio, (LIFE 11 ENV/GR/000949, 2012–2015), which is co-financed by the European Commission. The authors would like to thank Novozymes Corporation for generously providing the cellulase enzyme samples.
- 2.European Commission: Green paper—on the management of bio-waste in the European Union. Brussels (Belgium), 3 December 2008 (COM(2008) 811 final)Google Scholar
- 3.Lin, C.S.K., Pfaltzgraff, L.A., Herrero-Davila, L., Mubofu, E.B., Abderrahim, S., Clark, J.H., Koutinas, A.A., Kopsahelis, N., Stamatelatou, K., Dickson, F., Thankappan, S., Mohamed, Z., Brocklesby, R., Luque, R.: Food waste as a valuable resource for the production of chemicals, materials and fuels. Current situation and global perspective. Energy Environ. Sci. 6, 426–464 (2013)CrossRefGoogle Scholar
- 5.Commission, European: Directive 2003/30/EC of the European parliament and of the council of 8 May 2003 on the promotion of the use of biofuels or other renewable fuels for transport. Off. J. Eur. Union L. 123, 42–46 (2003)Google Scholar
- 12.Sotiropoulos, A., Malamis, D., Loizidou, M.: Pilot scale demonstration of food waste drying at household level. In: VENICE2012 Fourth International Symposium on Energy from Biomass and Waste, San Servolo, Venice, Italy, 12–15 November 2012Google Scholar
- 14.AOAC: Official Methods of Analysis of the Association of Official Analytical Chemists, 15th edn. AOAC Inc, USA (1990)Google Scholar
- 16.Sluiter, A., Hames, B., Ruiz, R., Scarlata, C., Sluiter, J., Templeton, D., Crocker, D.: Determination of structural carbohydrates and lignin in biomass. Technical report NREL/TP-510-42618 (2012)Google Scholar
- 24.Zheng, Y., Pan, Z., Zhang, R., Labavitch, J.M., Wang, D., Teter, S.A., Jenkins, B.M.: Evaluation of different biomass materials as feedstock for fermentable sugar production. Appl. Biochem. Biotechnol. 136–140, 423–435 (2007)Google Scholar
- 28.Wu, A., Lee, Y.Y.: Nonisothermal simultaneous saccharification and fermentation for direct conversion of lignocellulosic biomass to ethanol. Appl. Biochem. Biotechol. 70–72, 1109–1117 (1988)Google Scholar