Short Ozonation of Lignocellulosic Waste as Energetically Favorable Pretreatment
Lignocellulosic waste (here municipal trimmings) is a promising sustainable feedstock for ethanol production, but requires costly and polluting pretreatment, often resulting in toxic by-products. Ozonation, nonpolluting, effective pretreatment method, is not used commercially due to high energy requirements of ozone production at high ozone doses needed. Our results, however, demonstrated that low-dose ozonation (15 min, accumulated TOD = 318 mg L−1) of water-submerged waste resulted in improved enzymatic saccharification efficiency (31% of cellulose) compared to a non-ozonated sample (12%) although only 20% of the lignin was removed. Ozonation up to 90 min resulted in better conversion however exceptionally long ozonation (6 h and beyond) resulted in reduced conversion. These results suggest that contrary to common hypothesis, short ozonation could offer an effective and feasible pretreatment method for high sugar release without the need for delignification. In addition, the ozonation process was accompanied by changes in absorbance, mainly at 280 nm, making it a useful tool for process monitoring. Net calculated energy balance was positive for all ozonation regimes, with increased process efficiency at lower ozone doses. Furthermore, ozonation can be generated on-site and on demand, enabling decentralized pretreatment operated near the feed source, thus overcoming transportation costs.
KeywordsLignocellulosic waste Lignin Cellulose Ozone Ethanol Thermogravimetric analysis (TGA), municipal trimmings
We would like to thank Dr. Alex Golberg, Tel Aviv University, for his enormous help in the HPIC data analysis and for his advice. We also wish to thank Du-Pont Company for their donation of enzymes.
This research was conducted in the framework of the Israeli Ministry of National Infrastructure, Energy and Water Resources grant number 214-11-006, the Israeli Ministry of Environmental Protection grant number 132-3-4, and a scholarship from the Israeli Ministry of Science and Technology.
- 3.Ayalon O, Elimelech E, Spenser J, Zaban H, Lev-On M, Lev-On P (2008) Bioethanol in Israel: global context, research, planning and policy. Samuel Neaman Institute, Haifa, IsraelGoogle Scholar
- 15.Greenhot Z (2015) Agriculture byproducts in Israel. Report. Ministry of Environmental Protection, IsraelGoogle Scholar
- 32.Spectranomics Protocol (2011) Total phenol and tannin determination. Carnegie Institution for Science, Stanford, CAGoogle Scholar
- 37.Kukkola EM, Koutaniemi S, Pöllänen E, Gustafsson M, Karhunen P, Lundell TK, Saranpää P, Kilpeläinen I, Teeri TH, Fagerstedt KV (2004) The dibenzodioxocin lignin substructure is abundant in the inner part of the secondary wall in Norway spruce and silver birch xylem. Planta 218(3):497–500CrossRefGoogle Scholar
- 38.Abdul-Latif MH (2013) Qualitative and quantitative determination of lignin in different types of Iraqi Phoenix dactylifera Date palm pruning woods. J Nat Sci Res 3(6):71–77Google Scholar
- 40.Christensen JM, Rusch KA, Malone RE (2000) Development of a model for describing accumulation of color and subsequent destruction by ozone in a freshwater recirculating aquaculture system. J World Aquacult Soc 31(2):167–174. https://doi.org/10.1111/j.1749-7345.2000.tb00350.x CrossRefGoogle Scholar
- 43.Lee JM, Jameel H, Venditti RA (2010) Effect of ozone and autohydrolysis pretreatments on enzymatic digestibility of coastal Bermuda grass. BioResources 5(2):1084–1101Google Scholar