Biotechnology and Bioprocess Engineering 20: 139-147 (2015) DOI 10.1007/s12257-013-0535-6 Ethanol Production from Steam Exploded Rapeseed Straw and the Process Simulation Using Artificial Neural Networks Farid Talebnia, Moein Mighani, Mostafa Rahimnejad, and Irini Angelidaki Received: 13 August 2013 / Revised: 23 March 2014 / Accepted: 29 March 2014 © The Korean Society for Biotechnology and Bioengineering and Springer 2015 Abstract Rapeseed straw was utilized as a cheap raw material for ethanol production. Effects of steam explosion on chemical composition, enzymatic hydrolysis (EH) and simultaneous saccharification and fermentation (SSF) were studied. Changes in the pretreatment conditions showed strong effects on digestibility of the resulting straw. The optimum results were obtained at 180°C, 10% solid fraction, 1% H 2 SO 4 , and 10 min retention time. Under optimal condition, glucose hydrolysis yields of 93 and 89% were obtained for 5 and 10% solid fractions, respectively. The corresponding ethanol yields were 63 and 67% of maximum theoretical value. Next, data of the experimental runs were exploited for modeling the processes by artificial neural networks (ANNs) and performance of the developed models was evaluated. The ANN-based models showed a great potential for time-course prediction of the studied processes. Efficiency of the joint network for simulating the whole process was also determined and promising results were obtained. Keywords: rapeseed straw, steam explosion, fermentation, artificial neural network, bioprocess modeling 1. Introduction Global warming as one of the greatest social and environ- mental threats facing the planet has been the subject of intensive debate in recent years. The world CO 2 emissions have been drastically increased over the last few decades mainly due to human activities using fossil fuels in transportation/industrial sectors as well as land-use changes like deforestation. These facts along with the progressive depletion of global oil reserves have motivated researchers to develop alternative renewable energy resources. In line with these efforts, biomass-based fuels such as biodiesel and bioethanol have attracted great interest worldwide. Rapeseed (Brassica napus) is among biomasses that have been traditionally cultivated for animal feed and vegetable oil production [1]. In recent years, an increased portion of rapeseed oil has been used for biodiesel production. As a result, there has been an increase in annual production of rapeseed straw as a waste stream which can be used as a resource for energy production. The main advantage of producing ethanol from ligno- cellulosic feedstocks such as rape straw is the availability of abundant and diverse raw materials compared with the currently utilized resources, i.e. corn and cane sugars. Besides, cellulosic ethanol can contribute to the reduced greenhouse gas emissions. However, this technology requires more processing steps in order to make sugar monomers available to the microorganisms for fermentation [2]. Pretreatment, enzymatic hydrolysis and fermentation are three main steps required for cellulosic ethanol production. Among various pretreatment methods, steam explosion (SE) is one of the most cost-effective methods for ligno- cellulosic biomass [3,4]. In this method, size-reduced biomass is rapidly heated by high pressure steam for a period of time and then pressure is suddenly reduced, which Farid Talebnia * , Moein Mighani, Mostafa Rahimnejad Faculty of Chemical Engineering, Noshirvani University of Technology, Babol, Iran Tel: +98-11-3233 4204; Fax: +98-11-3233 4204 E-mail: f.talebnia@nit.ac.ir Irini Angelidaki Department of Environmental Engineering, Technical University of Denmark, Lyngby 2800, Denmark RESEARCH PAPER