ORIGINAL PAPER Comparative potentiality of Kans grass (Saccharum spontaneum) and Giant reed (Arundo donax) as lignocellulosic feedstocks for the release of monomeric sugars by microwave/chemical pretreatment Tidarat Komolwanich • Patomwat Tatijarern • Sirirat Prasertwasu • Darin Khumsupan • Thanyalak Chaisuwan • Apanee Luengnaruemitchai • Sujitra Wongkasemjit Received: 8 August 2013 / Accepted: 27 December 2013 / Published online: 10 January 2014 Ó Springer Science+Business Media Dordrecht 2014 Abstract Two-stage microwave (microwave/NaOH pretreatment followed by microwave/H 2 SO 4 pretreat- ment) was used to release monomeric sugars from Kans grass (Saccharum spontaneum) and Giant reed (Arundo donax). The optimum pretreatment condi- tions were investigated, and the maximum monomeric sugar yields were compared. The microwave-assisted NaOH and H 2 SO 4 pretreatments with a 15:1 liquid-to- solid ratio were studied by varying the chemical concentration, reaction temperature, and reaction time to optimize the amount of monomeric sugars. The maximum amounts of monomeric sugars released from microwave-assisted NaOH pretreatment were 6.8 g/100 g of biomass [at 80 °C/5 min, 5 % (w/v) NaOH for S. spontaneum and at 120 °C/5 min, 5 % (w/v) NaOH for A. donax]. Furthermore, the maxi- mum amounts of monomeric sugars released from microwave-assisted H 2 SO 4 pretreatment of S. sponta- neum and A. donax were 33.8 [at 200 °C/10 min, 0.5 % (w/v) H 2 SO 4 ] and 31.9 [at 180 °C/30 min, 0.5 % (w/v) H 2 SO 4 ] g/100 g of biomass, respectively. The structural changes of S. spontaneum and A. donax were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. Keywords Saccharum spontaneum  Arundo donax  Lignocellulosic biomass  Two-stage pretreatment  Microwave irradiation Introduction The growth of the world population and industrial prosperity has brought an inevitable increase in energy consumption. Fossil fuels have been the major resources used to respond to the rising energy demand (Sun and Cheng 2002). The use of these resources, however, has been accompanied by many problems regarding the cost, petroleum drilling technology, and global warming. Thus, researchers are endeavoring to find another source of energy. Ethanol presents one feasible source of alternative energy to replace fossil fuels (Jeffries 2006). Bioethanol is a good alternative for transportation fuel because of its economic, environmental, and strategic attributes (Bai et al. 2008). Presently, sugar- and starch-based raw materials are utilized in the production of bioethanol. However, the increasing human population and fuel demand make these raw materials insufficient for bioethanol production. Thus, researchers are attempting to use lignocellulosic biomass as a resource for bioethanol (Li et al. 2010). T. Komolwanich  P. Tatijarern  S. Prasertwasu  D. Khumsupan  T. Chaisuwan  A. Luengnaruemitchai  S. Wongkasemjit (&) The Petroleum and Petrochemical College and the National Center of Excellence for Petroleum, Petrochemicals, and Advanced Materials, Chulalongkorn University, Bangkok 10330, Thailand e-mail: dsujitra@chula.ac.th 123 Cellulose (2014) 21:1327–1340 DOI 10.1007/s10570-013-0161-7