Purdue University Purdue e-Pubs Open Access Dissertations Theses and Dissertations 4-2016 Enhancing Bioethanol Fermentation through Removal of Acetic Acid Using Liquid-Liquid Extraction Mahdieh Aghazadeh Purdue University Follow this and additional works at: https://docs.lib.purdue.edu/open_access_dissertations Part of the Agriculture Commons, and the Bioresource and Agricultural Engineering Commons Recommended Citation Aghazadeh, Mahdieh, "Enhancing Bioethanol Fermentation through Removal of Acetic Acid Using Liquid-Liquid Extraction" (2016). Open Access Dissertations. 614. https://docs.lib.purdue.edu/open_access_dissertations/614 This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. Graduate School Form 30 Updated PURDUE UNIVERSITY GRADUATE SCHOOL Thesis/Dissertation Acceptance This is to certify that the thesis/dissertation prepared By Mahdieh Aghazadeh Entitled Enhancing Bioethanol Fermentation Through Removal of Acetic Acid Using Liquid-Liquid Extraction For the degree of Doctor of Philosophy Is approved by the final examining committee: Abigail Engelberth John Howarter Chair Michael Ladisch Nien-Hwa Linda Wang Nathan Mosier To the best of my knowledge and as understood by the student in the Thesis/Dissertation Agreement, Publication Delay, and Certification Disclaimer (Graduate School Form 32), this thesis/dissertation adheres to the provisions of Purdue University’s “Policy of Integrity in Research” and the use of copyright material. Approved by Major Professor(s): Abigail Engelberth Approved by: Bernard Engel 4/15/2016 Head of the Departmental Graduate Program Date i ENHANCING BIOETHANOL FERMENTATION THROUGH REMOVAL OF ACETIC ACID USING LIQUID-LIQUID EXTRACTION A Dissertation Submitted to the Faculty of Purdue University by Mahdieh Aghazadeh In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy May 2016 Purdue University West Lafayette, Indiana ii ACKNOWLEDGEMENTS This work was made possible by direct or indirect help, support, suggestions, encouragement, and constructive criticism by my mentors, colleagues, and friends. I was truly fortunate to have Dr. Abigail S. Engelberth as my academic advisor and professional mentor. Her patience, encouragement, and direction have had undeniable impact in every single step of this research and work. She was always open and available to answer any question or direct me to find those answers myself and never hesitant to encourage me for good work or criticize me when needed. My committee members, Dr. Michael Ladisch, Dr. Nathan Mosier, Dr. John Howarter, and Dr. Nien-Hwa Linda Wang have given me phenomenal support and guidance throughout my years at Purdue. My colleagues at LORRE, Xingya Liu, Tommy Kreke, Dr. Eduardo Ximenes, Daehwan Kim, Dr. Ximing Zhang, David Orrego, and many others who helped me at different stages of my experiment design, laboratory work, and data interpretations. I would like to thank ABE staff, Scott Brand and Nate Engelberth, for their help in setting up the reactor; and the statistical consulting services, Dr. Kuczek and Dr. Jing Li, for their advice in data analysis. iii My family and friends, Mahtob, Mehran, Mehrdad, Leila, Jinsha, Mine, Maryam, Abby, Studie, Iman, Marcia, Jen, Emma, Shahrzad, Joyatee, and many, many others who unconditionally supported me with their unlimited wit and patience. Last but not least I would like to extend my greatest gratitude to my partner for life, Oren, for his unbelievable patience, great empathy, incredible counseling, and refreshing culinary art. iv TABLE OF CONTENTS Page LIST OF TABLES ....................................................................................................... vii LIST OF FIGURES ....................................................................................................... ix ABSTRACT ................................................................................................................. xi CHAPTER 1. INTRODUCTION ................................................................................. 1 1.1 Research Motivations .............................................................................................1 1.1.1 Bioethanol .....................................................................................................1 1.1.2 Fermentation inhibitors .................................................................................2 1.2 Research Objectives ...............................................................................................7 1.2.1 Solvent selection for the liquid-liquid extraction separation ...........................7 1.2.2 Fermentation performance after applying liquid-liquid extraction ..................7 1.2.3 Techno-economic analysis of the liquid-liquid extraction system ..................8 CHAPTER 2. REVIEW OF FERMENTATION INHIBITOR REMOVAL TECHNIQUES .............................................................................................................. 9 2.1 Inhibition mechanism of acetic acid ........................................................................9 2.2 Separation methods to remove the inhibitors ........................................................ 11 2.2.1 Membrane Separation ................................................................................. 11 2.2.2 Adsorption studies....................................................................................... 14 2.2.3 Liquid-liquid extraction studies ................................................................... 17 2.3 Challenges regarding liquid-liquid extraction ....................................................... 20 2.4 Conclusion ........................................................................................................... 22 CHAPTER 3. EXPLORATION INTO LIQUID-LIQUID EXTRACTION SOLVENTS TO REMOVE SACCHAROMYCES CEREVISIAE INHIBITORS .................................. 24 3.1 Abstract ................................................................................................................ 24 3.2 Introduction .......................................................................................................... 25 3.3 Materials and Methods ......................................................................................... 27 3.3.1 Simulation ................................................................................................... 27 3.3.2 Laboratory Experiment and Analysis........................................................... 27 v Page 3.4 Results and Discussion ......................................................................................... 28 3.4.1 Simulation: Narrowing Down the Solvents .................................................. 29 3.4.2 Experimental: Acetic Acid Extraction ......................................................... 30 3.4.3 Simulation: Extraction of Other Common Inhibitors ................................... 34 3.5 Conclusion ........................................................................................................... 38 CHAPTER 4. ACETIC ACID REMOVAL FROM CORN STOVER HYDROLYSATE USING ETHYL ACETATE AND THE IMPACT ON SACCHAROMYCES CEREVISIAE BIOETHANOL FERMENTATION .............................................................................. 39 4.1 Abstract ................................................................................................................ 39 4.2 Introduction .......................................................................................................... 40 4.3 Materials and Methods ......................................................................................... 44 4.3.1 Materials ..................................................................................................... 44 4.3.2 Biomass Preparation and Pretreatment ........................................................ 44 4.3.3 Selection of Solvent Candidates Using Aspen Plus .................................. 46 4.3.4 Liquid-liquid extraction ............................................................................... 46 4.3.5 Synergistic Inhibition Experimental Design ................................................ 47 4.3.6 Evaporation ................................................................................................. 48 4.3.7 Fermentation ............................................................................................... 48 4.3.8 HPLC Analysis ........................................................................................... 49 4.3.9 Statistical Analysis ...................................................................................... 49 4.4 Results and Discussion ......................................................................................... 50 4.4.1 Solvent Selection Using Aspen Plus™ ........................................................ 50 4.4.2 Liquid-liquid Extraction .............................................................................. 52 4.4.3 Synergistic Inhibition of Ethyl Acetate and Acetic Acid .............................. 54 4.4.4 Solvent Recycle .......................................................................................... 59 4.4.5 Impact on Fermentation............................................................................... 60 4.5 Conclusion ........................................................................................................... 62 CHAPTER 5. TECHNO-ECONOMIC