섬유소계 바이오매스의 주요 구성요소 간의 관계에 의한 물리적, 화학적 장벽은 셀룰로오스를 발효 가능한 당으로 전환시키는 효소당화를 방해한다. 전처리의 주 목적은 셀룰로오스의 효소당화율을 향상시키기 위하여 기질로의 효소접근성을 높이는 것으로, 전처리 공정의 발전은 지속적으로 요구되고 있다. 본 연구에서는, 간단하고, 상대적으로 저비용인 암모니아수에 의한 침지공정을 전처리방법로 채택하였다. 기질로는 국내 농업 잔류물 중 생산량이 높은 볏짚을 채택하였다. 암모니아수에 의한 침지 공정은 3, 12, 24 그리고 72시간 동안 수행되었다. 그리고 동시당화발효에 미치는 전처리의 효과를 조사하기 위해, 효소당화와 동시당화발효를 30, 40 그리고 50 ℃에서 수행하였다. 연구 결과에 따르면, 볏짚이 암모니아수에 의한 침지 처리 되었을 때, 기존의 보편적인 동시당화발효와 비교하여 상대적으로 적은 효소사용량과 낮은 온도(30 ℃) 조건에서도 당화와 동시당화발효가 수행될 수 있음을 확인하였다. 그리고 암모니아수에 의한 침지 처리는 초기 당화속도를 증가시킴으로써 24시간 이내에 발효를 종료시켰다.

Physical and chemical barriers, caused by the close association of the main components of cellulosic biomass, hinder the hydrolysis of cellulose to fermentable sugars. Since the main goal of pretreatment is to increase the enzyme accessibility improving digestibility of cellulose, development of an effective pretreatment process has been considered to be important. In this study, SAA (Soaking in Aqueous Ammonia) was chosen as pretreatment because this is the simple and low-cost method. Rice straw of which the production is outstandingly high in domestic agriculture residues in Korea was chosen as raw material. SSA pretreatment with various reaction time of 3 h to 72 h was tested. The enzymatic hydrolysis and SSF (Simultaneous Saccharification and Fermentation) were performed at three different temperature (30, 40 and 50 ℃) to investigate performance of SSF upon various pretreatment conditions. As a result, this_x000D_ SAA treated-rice straw was found to have great potential for effective enzymatic hydrolysis and SSF with lower enzyme dosage at lower temperature (30 ℃) than its conventional SSF. In SAA addition, SAA reduced fermentation time to 24 h owing to increase the initial hydrolysis rate substantially.

SSF SAA Pretreatment Enzymatic Hydrolysis

Lynd LR, Elander RT, Wyman CE, “Likely Features and Costs of Mature Biomass Ethanol Technology,” Biochem. Biotechnol., 57/58, 741-761 (1996)
Lee D, Yu AHC, Wong KKY, Saddler JN, “Evaluation of the Enzymatic Susceptibility of Cellulosic Substrates using Specific Hydrolysis Rates and Enzyme Adsorption,” Biochem. Biotechnol., 45/46, 407-415 (1994)
Mosier N, Wyman C, Dale B, Elander R, Lee YY, Holtzapple M, Ladisch M, Bioresour. Technol., 96(6), 673 (2005)
Kim TH, Korean J. Chem. Eng., 29(1), 82 (2012)
Kim TH, Lee YY, “Pretreatment of Corn Stover by Soaking in Aqueous Ammonia at Moderate Temperature,” Biochem. Biotechnol., 137/140, 81-92 (2007)
Kim TH, Lee YY, Bioresour. Technol., 97(2), 224 (2006)
Mooney CA, Mansfield SD, Touhy MG, Saddler JN, Bioresour. Technol., 64(2), 113 (1998)
Tao L, Aden A, Elander RT, Pallapolu VR, Lee YY, Garlock RJ, Balan V, Dale BE, Kim Y, Mosier NS, Ladisch MR, Falls M, Holtzapple MT, Sierra R, Shi J, Ebrik MA, Redmond T, Yang B, Wyman CE, Hames B, Thomas S, Warner RE, Bioresour. Technol., 102(24), 11105 (2011)
Park YC, Kim JS, Korean Chem. Eng. Res., 49(4), 470 (2011)
Ko JK, Bak JS, Jung MW, Lee HJ, Choi IG, Kim TH, Kim KH, Bioresour. Technol., 100(19), 4374 (2009)
Skotmicki ML, Lee KJ, Tribe DE, Rogers PL, Environ. Microbiol., 41, 889 (1981)
Lin Y, Tanaka S, Appl. Microbiol. Biotechnol., 69(6), 627 (2006)