본 연구는 농업 부산물인 옥수수대(corn stover)를 이용하여 묽은 황산법(DSA; dilute sulfuric acid)과 암모니아 침지법(SAA; soaking in aqueous ammonia) 그리고 암모니아 재순환 침출법(ARP; ammonia recycle percolation)을 비교하여 각 전처리법의 특징과 장단점을 분석하였고, 동시당화공동발효를 통한 에탄올 생산을 비교하였다. ARP, DSA, SAA를 이용하여 전처리된 고형물(3% 글루칸 투입)을 15 FPU/g-glucan, 30 CBU/g-glucan의 상업용 효소(Spezyme CP와 Novozyme 188;)와 E. coli KO11 균주(ATCC® 55124)를 이용하여 동시당화공동발효를 수행하였다. 전처리 후에 남은 고형물에 있는 당의 최대이론적 에탄올 수율은 각각 87, 90 그리고 78%였다. 이것은 전처리되지 않은 원래 옥수수대의 총 당량(글루칸 +자일란) 대비 각각 69, 58, 및 74%에 해당하는 것으로 SAA의 수율이 가장 높게 관찰되었다. 또한 전처리 당화액을 이용한 동시당화공동발효 실험결과는 DSA의 당화액이 발효균주에 대하여 가장 높은 독성을 나타내었고 ARP 전처리 당화액이 그 다음으로 저해효과가 큰 것으로 나타났다. 결국 SAA를 이용하여 전처리한 후 리그닌이 풍부한 당화액은 이용하지 않고 전처리된 고형물과 동시당화공동발효 공정을 이용한 에탄올 생산이 가장 간단하면서 경제적인 공정으로 제안되었다.

This is to study the effects of various pretreatment methods of agricultural residue, corn stover, and to compare the feature and pros and cons of each method including dilute sulfuric acid(DSA), soaking in aqueous ammonia (SAA), and ammonia recycle percolation (ARP). In order to convert corn stover to ethanol, various pretreatments followed by simultaneous saccharification and co-fermentation (SSCF) were tested and evaluated in terms of ethanol yield. With 3%, w/w of glucan loading using ARP-, DSA-, and SAA-treated solids, SSCFs using recombinant E. coli strain (ATCC® 55124) with commercial enzymes (15 FPU of Spezyme CP/g-glucan and 30 CBU/g-glucan enzyme loading) were tested. In the SSCF tests, 87, 90, and 78% of theoretical maximum ethanol yield were observed using ARP-, DSA-, and SAA-treated solids, respectively, which were 69, 58, and 74% on the basis of total carbohydrates (glucan + xylan) in the untreated corn stover. Ethanol yield of SAA-treated solid was higher than those of ARP- and DSA-treated solids. In addition, SSCF test using treated solids plus pretreated hydrolysate indicated that the DSA-treated hydrolysate showed the strongest inhibition effect on the KO11 strain, whereas the ARP-treated hydrolysate was found to have the second strongest inhibition effect. Bioconversion scheme using SAA pretreatment and SSCF can make the downstream process simple, which is suggested to produce ethanol economically because utilization of hemicellulose in the hydrolysate is not necessary.

Bioenergy Bioethanol Cellulose Hemicellulose Pretreatment

Kamm B, Gruber PR. Kamm M, Biorefineries - Industrial Processes and Products, Wiley-VCH Weinheim (2007)
Mosier N, Wyman CE, Dale BE, Elander R, Lee YY, Holtzapple M, Bioresour. Technol., 96, 673 (2005)
Fernandez-Bolanos J, Felizon B, Heredia A, Guillen R, Jimenez A, Bioresour. Technol., 68(2), 121 (1999)
Sawada T, Nakamura Y, Kobayashi F, Kuwahara M, Watanabe T, Biotechnol. Bioeng., 48(6), 719 (1995)
Schwald W, Brownell HH, Saddler JN, J. Wood Chem. Technol., 8(4), 543 (1988)
Kim TH, Lee YY, Appl. Biochem. Biotechnol., 121, 1119 (2005)
Kim TH, Kim JS, Sunwoo C, Lee YY, Bioresour. Technol., 90(1), 39 (2003)
Kim TH, Lee YY, Bioresour. Technol., 96(18), 2007 (2005)
Kim TH, Lee YY, Bioresour. Technol., 97(2), 224 (2006)
Iyer PV, Wu Z, Kim SB, Lee YY, Appl. Biochem. Biotechnol., 57, 121 (1996)
Jacobsen SE, Wyman CE, Appl. Biochem. Biotechnol., 84, 81 (2000)
Kim JS, Lee YY, Torget RW, Appl. Biochem. Biotechnol., 91, 331 (2001)
Allen SG, Schulman D, Lichwa J, Antal MJ, Laser M, Lynd LR, Ind. Eng. Chem. Res., 40(13), 2934 (2001)
Park YC, Kim JW, Kim JS, Korean Chem. Eng. Res., 49(3), 292 (2011)
Holtzapple MT, Lundeen JE, Sturgis R, Lewis JE, Dale BE, “Pretreatment of Lignocellulosic Municipal Solid Waste by Ammonia Fiber Explosion (AFEX),” Appl. Biochem. Biotechnol., 34-35(1), 5-21 (1992)
Zhu YM, Lee YY, Elander RT, Appl. Biochem. Biotechnol., 117(2), 103 (2004)
Wyman C, Handbook on Bioethanol: Production and Utilization, Taylor & Francis, Washington D.C. (1996)
Shrestha R, Hur O, Kim TH, Korean Chem. Eng. Res., 51(3), 335 (2013)
Hahn-Hagerdal B, Jeppsson H, Olsson L, Mohagegi A, Appl. Biochem. Biotechnol., 41, 62 (1994)
Sluiter A, Hames B, Ruiz R, Scarlata C, Sluiter J, Tmpleton D, Crocker D, “Determination of Structural Carbohydrates and Lignin in Biomass,” National Renewable Energy Laboratory NREL/TP-510-42618 ed. Golden, CO (2010)
Sluiter A, Hames B, Ruiz R, Scarlata C, Sluiter J, Tmpleton D, “Determination of Sugars, Byproducts, and Degradation Products in Liquid Fraction Process Samples,” National Renewable Energy Laboratory NREL/TP-510-42623 ed. Golden, CO (2008)
Selig M, Weiss N, Ji Y, “Enzymatic Saccharification of Lignocellulosic Biomass,” National Renewable Energy Laboratory NREL/TP-510-42629 ed. Golden, CO (2008)
Dowe N, McMillan J, “SSF Experimental Protocols-ligno- Cellulosic Biomass Hydrolysis and Fermentation,” National Renewable Energy Laboratory NREL/TP-510-42630 ed. Golden, CO (2008)
de Mancilha IM, Karim MN, Biotechnol. Prog., 19(6), 1837 (2003)