Hydrolysis of bamboo biomass by subcritical water treatment Mood Mohan, Tamal Banerjee, Vaibhav V. Goud ⇑ Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India highlights  Reaction temperature and time shown more impact on total reducing sugars yield.  Highest yield of total reducing sugars obtained at 180 °C and 25 min of reaction time.  X-ray diffraction profile shown increase in crystallinity index after treatment.  Kinetics of bamboo was considered as first-order irreversible series reaction. graphical abstract Feed stock (Bamboo) Cellulose Hemicellulose Amorphous Region Crystalline Region Lignin Hydrolysis at high temperature Water Inlet Water Outlet Auto Cooler Nitrogen Gas cylinder sample outlet Gas outlet Steam outlet Stirrer Reactor Stand Pressure Gauge Controller Cellulose Hemicellulose Liquid f raction Solid f raction HPLC analysis XRD, FTIR, SEM analysis Reducing sugars quantification SCW Treatment condition: Temperature = 170 - 220 o C Time = 5 - 40 min Lignin article info Article history: Received 9 March 2015 Received in revised form 5 May 2015 Accepted 6 May 2015 Available online 13 May 2015 Keywords: Bamboo Total reducing sugars Subcritical water treatment Reaction kinetics abstract The aim of present study was to obtain total reducing sugars (TRS) from bamboo under subcritical water (SCW) treatment in a batch reactor at the temperature ranging from 170 °C to 220 °C and 40 min hydrolysis time. Experiments were performed to investigate the effects of temperature and time on TRS yield. The maximum TRS yield (42.21%) was obtained at lower temperature (180 °C), however longer reaction time (25 min). X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) analysis were used to characterise treated and untreated bamboo samples. The XRD profile revealed that crystallinity of bamboo increased to 71.90% with increase in temperature up to 210 °C and decreased thereafter to 70.92%. The first-order reaction kinetic model was used to fit the experimental data to obtain rate constants. From the Arrhenius plot, activation energy and pre-exponential factor at 25 min time were found to be 17.97 kJ mol 1 and 0.154 min 1 , respectively. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction The continuous increase in the population growth pushes towards expanding the utilisation of fossil assets in the production of energy and chemicals (Mohan et al., 2015b). The high utilisation rate of fossil resources has a direct impact on the economic, envi- ronmental, political, life quality of population and also increases emission of greenhouse gases, which aggravate global warming. Hence it requires an alternative energy solution to decrease today’s rapid consumption of fossil resources. A potential alternative solu- tion to this problem could be utilisation of lignocellulosic biomass as an alternative energy source for the future (Holm and Lassi, 2011). Currently extensive research is being undertaken to produce environmentally friendly energy power and worth included chem- icals from lignocellulosic biomass (Mohan et al., 2015a, 2015b). Use of biomass for energy avoids the increase of CO 2 in the atmo- sphere (Asghari and Yoshida, 2010). As per the facts, aggregate energy prepared from photosynthesis is ten times higher than that of the fossil-fuel assets utilised within the world consistently (Wang et al., 2010). http://dx.doi.org/10.1016/j.biortech.2015.05.010 0960-8524/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +91 361 2582272; fax: +91 361 2582291. E-mail addresses: tamalb@iitg.ernet.in (T. Banerjee), vvgoud@iitg.ernet.in (V.V. Goud). Bioresource Technology 191 (2015) 244–252 Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech