期刊论文

【摘要】

Background

Forest residue is one of the most cost-effective feedstock for biofuel production. It has relatively high bulk density and can be harvested year round, advantageous for reducing transportation cost and eliminating onsite storage. However, forest residues, especially those from softwood species, are highly recalcitrant to biochemical conversion. A severe pretreatment for removing this recalcitrance can result in increased sugar degradation to inhibitors and hence cause difficulties in fermentation at high solid loadings. Here, we presented high titer ethanol production from Douglas-fir forest residue without detoxification. The strong recalcitrance of the Douglas-fir residue was removed by sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL). Sugar degradation to inhibitors was substantially reduced using a novel approach of “pH profiling” by delaying acid application in pretreatment, which facilitated the simultaneous enzymatic saccharification and fermentation of undetoxified whole slurry at a solid loading of 21%.

Results

“pH profiling” reduced furan production by approximately 70% in using SPORL pretreating Douglas-fir forest residue (FS-10) comparing with the control run while without sacrificing enzymatic saccharification of the resultant substrate. pH profiling also reduced carbohydrate degradation. The improved carbohydrate yield in pretreated solids and reduced fermentation inhibitors with pH profiling resulted in a terminal ethanol titer of 48.9 ± 1.4 g/L and yield of 297 ± 9 L/tonne FS-10, which are substantially higher, i.e., by 27% in titer and by 38% in yield, than those of a control SPORL run without pH profiling.

Conclusions

Economical and large-volume production of commodity biofuels requires the utilization of feedstocks with low value (therefore low cost) and sustainably producible in large quantities, such as forest residues. However, most existing pretreatment technologies cannot remove the strong recalcitrance of forest residues to produce practically fermentable high titer sugars. Here, we demonstrated a commercially scalable and efficient technology capable of removing the strong recalcitrant nature of forest residues using “pH profiling” together with “low temperature SPORL”. The resultant pretreated whole slurry of a Douglas-fir forest residue using this technology can be easily processed at high solids of 21% without detoxification to achieve a high ethanol yield of 297 L/tonne at 48.9 g/L.

Graphical Abstract. Graphic table of content.

【授权许可】

2015 Cheng et al.; licensee BioMed Central.

【参考文献】

[1]Larsson S, Palmqvist E, Hahn-Hagerdal B, Tengborg C, Stenberg K, Zacchi G, et al.: The generation of fermentation inhibitors during dilute acid hydrolysis of softwood. Enzyme Microb Technol. 1999, 24:151-9.
[2]Zhu W, Houtman CJ, Zhu JY, Gleisner R, Chen KF: Quantitative predictions of bioconversion of aspen by dilute acid and SPORL pretreatments using a unified combined hydrolysis factor (CHF). Process Biochem. 2012, 47:785-91.
[3]Zhu JY, Pan XJ, Wang GS, Gleisner R: Sulfite pretreatment (SPORL) for robust enzymatic saccharification of spruce and red pine. Bioresour Technol 2009, 100(8):2411-8.
[4]Pan XJ, Gilkes N, Kadla J, Pye K, Saka S, Gregg D, et al.: Bioconversion of hybrid poplar to ethanol and co-products using an organosolv fractionation process: optimization of process yields. Biotechnol Bioeng 2006, 94(5):851-61.
[5]Cantarella M, Cantarella L, Gallifuoco A, Spera A, Alfani F: Effect of inhibitors released during steam-explosion treatment of poplar wood on subsequent enzymatic hydrolysis and SSF. Biotechnol Prog 2004, 20(1):200-6.
[6]Soderstrom J, Galbe M, Zacchi G: Effects of washing on yield in one- and two-step steam pretreatment of softwood for production of ethanol. Biotechnol Prog. 2004, 20:744-9.
[7]Chen X, Shekiro J, Franden MA, Wang W, Zhang M, Kuhn E, et al.: The impacts of deacetylation prior to dilute acid pretreatment on the bioethanol process. Biotechnol Biofuels. 2012, 5:8. BioMed Central Full Text
[8]Zhang C, Houtman CJ, Zhu JY: Using low temperature to balance enzymatic saccharification and furan formation in SPORL pretreatment of Douglas-fir. Process Biochem. 2014, 49:466-73.
[9]Zhu JY, Chandra MS, Gu F, Gleisner R, Reiner R, Sessions J, et al.: Using sulfite chemistry for robust bioconversion of Douglas-fir forest residue to bioethanol at high titer and lignosulfonate: a pilot-scale evaluation. Bioresour Technol 2015, 179:390-7.
[10]National Research Council: Renewable Fuel Standard: Potential Economic and Environmental Effects of U.S. Biofuel Policy. http://www.nap.edu/openbook.php?record_id=13105 2011, ISBN 978-0-309-18751-0.
[11]Perlack RD, Stokes BJ: U.S. Billion-Ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry. DOE Report DE-AC05-00R22725, Oakridge National Laboratory, 2011.
[12]Kirschbaum MUF: To sink or burn? A discussion of the potential contributions of forests to greenhouse gas balances through storing carbon or providing biofuels. Biomass Bioenerg 2003, 24(4–5):297-310.
[13]Gan J, Smith CT: Availability of logging residues and potential for electricity production and carbon displacement in the USA. Biomass Bioenerg 2006, 30(12):1011-20.
[14]Stephen JD, Mabee WE, Saddler JN: Biomass logistics as a determinant of second-generation biofuel facility scale, location, and technology selection. Biofpr. 2010, 4:503-18.
[15]Zhu JY, Zhuang XS: Conceptual net energy output for biofuel production from lignocellulosic biomass through biorefining. Prog Energ Combustion Sci 2012, 38(4):583-9.
[16]Leu S-Y, Gleisner R, Zhu JY, Sessions J, Marrs G: Robust enzymatic saccharification of a Douglas-fir forest harvest residue by SPORL. Biomass Bioenerg. 2013, 59:393-401.
[17]Zhou H, Leu S-Y, Wu X, Zhu JY, Gleisner R, Yang D, et al.: Comparisons of high titer ethanol production and lignosulfonate properties by SPORL pretreatment of lodgepole pine at two temperatures. RSC Adv. 2014, 4:27033-8.
[18]Ingruber O: Sulfite science, part I: sulfite pulping cooking liquor and the four bases. In: Sulfite Science and Technology. Edited by Ingruber O, Kocurek M, Wong A, vol. 4, 3rd edition. Atlanta: The joint textbook Committee of the Paper Industry, TAPPI/CPPA; 1985: 3–23.
[19]Tunc MS, Van Heiningen ARP: Hemicellulose extraction of mixed southern hardwood with water at 150°C: effect of time. Industr Eng Chem Res 2008, 47(18):7031-7.
[20]Leu SY, Zhu JY: Substrate-related factors affecting enzymatic saccharification of lignocelluloses: our recent understanding. Bioenerg Res 2013, 6(2):405-15.
[21]Wang QQ, He Z, Zhu Z, Zhang Y-HP, Ni Y, Luo XL, et al.: Evaluations of cellulose accessibilities of lignocelluloses by solute exclusion and protein adsorption techniques. Biotechnol Bioeng 2012, 109(2):381-9.
[22]Yang B, Wyman CE: Effect of xylan and lignin removal by batch and flowthrough pretreatment on the enzymatic digestibility of corn stover cellulose. Biotechnol Bioeng 2004, 86(1):88-95.
[23]Rollin JA, Zhu Z, Sathitsuksanoh N, Zhang Y-HP: Increasing cellulose accessibility is more important than removing lignin: a comparison of cellulose solvent-based lignocellulose fractionation and soaking in aqueous ammonia. Biotechnol Bioeng 2011, 108(1):22-30.
[24]Jeoh T, Ishizawa CI, Davis MF, Himmel ME, Adney WS, Johnson DK: Cellulase digestibility of pretreated biomass is limited by cellulose accessibility. Biotechnol Bioeng 2007, 98(1):112-22.
[25]Zhou H, Zhu JY, Luo X, Leu S-Y, Wu X, Gleisner R, et al.: Bioconversion of beetle-killed lodgepole pine using SPORL: process scale-up design, lignin coproduct, and high solids fermentation without detoxification. Ind Eng Chem Res 2013, 52(45):16057-65.
[26]Croon I: The flexibility of sodium-based two-stage neutral-acid sulfite pulping. In: Pulp Paper Mag Canada, February 1965:T71-T76.
[27]Lagergren S: The Stora pulping process and its implications for European paper makers. Svensk Papperstidning 1964, 67(238–243).
[28]Sanyer N, Keller EL, Chidester GH: Multistage sulfite pulping of jack pine, balsam fir, spruce, oak, and sweetgum. TAPPI 1962, 45(2):90-104.
[29]Zhou H, Zhu JY, Gleisner R, Qiu X, Horn E, Negron J: Pilot-scale demonstration of SPORL for bioconversion of lodgepole pine to bio-ethanol and lignosulfonate. Holzforschung. 2015; 69, DOI: 10.1515/hf-2014-0332.
[30]Zhang C, Zhu JY, Gleisner R, Sessions J: Fractionation of forest residues of Douglas-fir for fermentable sugar production by SPORL pretreatment. Bioenergy Res 2012, 5(4):978-88.
[31]Wood TM, Bhat M: Methods for measuring cellulase activities. In: In: Colowick SP, Kaplan NO, editors Methods in Enzymology, Vol 160, Biomass(Part A, Cellulose and Hemicellulose) Vol editors:Wood WA, Kellogg ST. New York: Academic Press, Inc, 1988: 87–112.
[32]Hector RE, Dien BS, Cotta MA, Qureshi N: Engineering industrial Saccharomyces cerevisiae strains for xylose fermentation and comparison for switchgrass conversion. J Ind Microbiol Biotechnol 2011, 38(9):1193-202.
[33]Zhu JY, Wang GS, Pan XJ, Gleisner R: Specific surface to evaluate the efficiencies of milling and pretreatment of wood for enzymatic saccharification. Chem Eng Sci 2009, 64(3):474-85.
[34]Lan TQ, Lou H, Zhu JY. Enzymatic saccharification of lignocelluloses should be conducted at elevated pH 5.2–6.2. Bioenerg Res. 2013;6(2):476–85.
[35]Lou H, Zhu JY, Lan TQ, Lai H, Qiu X: pH-induced lignin surface modification to reduce nonspecific cellulase binding and enhance enzymatic saccharification of lignocelluloses. ChemSusChem 2013, 6(5):919-27.
[36]Wang ZJ, Lan TQ, Zhu JY: Lignosulfonate and elevated pH can enhance enzymatic saccharification of lignocelluloses. Biotechnol Biofuels. 2013, 6:9. BioMed Central Full Text
[37]Luo X, Gleisner R, Tian S, Negron J, Horn E, Pan XJ, et al.: Evaluation of mountain beetle infested lodgepole pine for cellulosic ethanol production by SPORL pretreatment. Ind Eng Chem Res 2010, 49(17):8258-66.
[38]Dence CW: The determination of lignin. In: Methods in lignin chemistry. Edited by Lin SY, Dence CW. Berlin: Springer-Verlag; 1992: 33–61.

Biotechnology for Biofuels
High titer and yield ethanol production from undetoxified whole slurry of Douglas-fir forest residue using pH profiling in SPORL

Jinlan Cheng² Shao-Yuan Leu¹ JY Zhu² Rolland Gleisner²
[1] Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Kowloon, Hong Kong
[2] USDA Forest Service, Forest Products Laboratory, Madison 53719, WI, USA
关键词: High-titer biofuel; Fermentation inhibitors; High solids processing; Enzymatic hydrolysis and fermentation; Forest residue;
Others : 1224868 DOI : 10.1186/s13068-015-0205-3

received in 2014-09-09, accepted in 2015-01-15, 发布年份 2015


	文献评价指标
	下载次数：0次	浏览次数：0次

【 摘 要 】