U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Bioenergy Research: Peoria, IL
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    Careers


        


                    NCAUR Homepage
                    About BER
                        Mission Statement
                                    Strategic Goals
                                    Specialized Research ResourcesSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area Peoria, Illinois National Center for Agricultural Utilization Research Bioenergy Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Research Project: Technologies for Improving Process Efficiencies in Biomass Refineries Location:
                                Bioenergy Research Title:   Author  item
                                            XUE, SAISI - Michigan State Universityitem
                                            UPPUGUNDLA, NIRMAL - Michigan State Universityitem
                                            Bowman, Michaelitem
                                            CAVALIER, DAVID - Michigan State Universityitem
                                            DA COUSTA SOUSA, LEONARDO - Michigan State Universityitem
                                            DALE, BRUCE - Michigan State Universityitem
                                            BALAN, VENKATESH - Michigan State University
  Submitted to: Biotechnology for Biofuels and Bioproducts
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 11/5/2015
                                    Publication  Date: 11/26/2015
                                    Publication URL: http://handle.nal.usda.gov/10113/62507Citation: Xue, S., Uppugundla, N., Bowman, M.J., Cavalier, D., Da Cousta Sousa, L., Dale, B.E., Balan, V. 2015. Sugar loss and enzyme inhibition due to oligosaccharides accumulation during high solids-loading enzymatic hydrolysis. Biotechnology for Biofuels. 8:195. doi: 10.1186/s13068-015-0378-9.Interpretive Summary: High sugar concentrations are required in biomass fermentations to achieve high ethanol titers thereby reducing the energy required to distill the ethanol from fermentation broths; however, high solids loadings (e.g. 25% solid loading) required to achieve high sugar concentrations can interfere with the efficiency of the bioconversion process at a variety of levels.  Due to high solids loading, an accumulation of unhydrolyzed oligosaccharides occurs during enzymatic hydrolysis of cellulosic biomass reducing biofuel yields and increases processing costs for a cellulosic biorefinery.  These oligosaccharides accumulate to 18-25% of the total soluble sugars in the hydrolysate and represent a yield loss and can inhibit commercial hydrolytic enzymes hindering economical biofuel production from cellulosic biomass.  Little is known about the features of these oligomers that make them recalcitrant to commercial enzymes.  This work presents a robust method for separating recalcitrant oligosaccharides from high solid loading hydrolysate in gram quantities facilitating recalcitrance and enzyme inhibition studies.  Such studies can clarify:  the reasons for oligosaccharide accumulation; contribute to development of strategies to convert oligosaccharides into fermentable sugars to provide higher biofuel yields; and potentially reduce enzyme loadings.
                                Technical Abstract: Oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, ammonia fiber expansion: AFEX and extractive ammonia: EA). The methodology for large-scale separation of recalcitrant oligosaccharides from 25% solids-loading AFEX-corn stover hydrolysate (ACH) using charcoal fractionation and size exclusion chromatography is reported here for the first time. Oligosaccharides with higher degree of polymerization (DP) are recalcitrant towards commercial enzyme mixtures (Ctec2, Htec2 and Multifect pectinase (MP)) compared to lower DP oligosaccharides. Enzyme inhibition studies using isolated substrates (Avicel and xylan) show that low DP oligosaccharides also inhibit commercial enzymes. Addition of monomeric sugars to oligosaccharides increases the inhibitory effects of oligosaccharides on commercial enzymes.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov