A Comparison of Aqueous and Dilute-Acid Single-Temperature Pretreatment of Yellow Poplar Sawdust

Abstract

Pretreatment of fresh yellow poplar sawdust (<6 mm, 25−30 wt % moisture) with hot liquid water (190−220 °C, 2.0−7.5 min, 2−7 wt % solids loading) or steam (220 °C, 2.0 min) was compared with dilute acid pretreatment (0.8% w/v sulfuric acid, 175 °C, 10 min, 20−25 wt % solids loading). The most favorable conditions for hot liquid water pretreatment (220 °C, 2.0 min, 5 wt % solids loading) performed as well as the dilute acid pretreatment (175 °C, 10.0 min, 0.8% sulfuric acid, 20 wt % solids loading) for fermentation of the cellulosic fraction of the pretreated fibers by simultaneous saccharification and fermentation (SSF), using Saccharomyces cerevisiae and 25 IFPU cellulase/g of cellulose. Ethanol yields of 97 and 92 wt % of the theoretical yield and xylan recoveries of 85 and 70 wt % (92 and 96 wt % solubilization) were achieved with the hot liquid water and dilute acid pretreatments, respectively. Steam pretreatment (220 °C, 2 min) was not as effective as the dilute acid pretreatment, resulting in an ethanol yield of 70 wt % of the theoretical yield, with 88 wt % xylan recovery (54 wt % solubilization). A positive correlation was found between xylan removal and the ethanol yield obtained by SSF. Xylan recovery, however, was inversely proportional to xylan solubilization. Removal of up to 57 wt % of the acid-insoluble lignin in yellow poplar was also possible with hot liquid water pretreatment, with 75 wt % of this acid-insoluble lignin recoverable by simple filtration of the liquid pretreatment products.

Cellulase adsorption and relationship to features of corn stover solids produced by leading pretreatments

“…Lignin removal has often been shown to improve cellulose digestibility, with mechanisms postulated to be improved cellulose accessibility, enhancement of cellulase effectiveness by removal of cross linkages to carbohydrates, or both, (Chang and Holtzapple, 2000;Ohgren et al, 2007;Pan et al, 2005;Taniguchi et al, 2005;Yang and Wyman, 2004), but only a few studies claim lignin removal offers little benefit (Grohmann et al, 1986). Moreover, although xylan removal is often reported to enhance glucan digestibility (Allen et al, 2001;Ishizawa et al, 2007;Yang and Wyman, 2004;Zhu et al, 2005), a first of a kind of study showed that xylan removal enhanced biomass digestibility by increasing cellulose accessibility (Jeoh et al, 2007). Furthermore, removal of acetyl content has been reported to enhance digestibility (Chang and Holtzapple, 2000;Grohmann et al, 1989;Wood and McCrae, 1986), but its impact on cellulose accessibility has not been reported.…”

Improved Ethanol Production from Deacetylated Yellow Poplar (Liriodendron tulipifera) by Detoxification of Hydrolysate and Semi-SSF

“…리그노셀룰로오스계 바이오매스는 재생가능 하며 풍부한 탄수화물을 포함하고 있어 바이오에탄올 생산에 적합한 자원으로 알려져 있다 [3]. 특히 백합나무(Yellow poplar, Liriodendron tulipifera)는 다른 수종에 비해 목재 구성성분 중 리그닌이 차지하는 비율이 적고, 생장 속도가 빠른 특징으로 그 이용이 용이하다 [4].…”

Optimum Enzyme Mixture of Cellulase, Hemicellulase, and Xylanase for Production of Water-Soluble Carbohydrates from Rice Straw

“…섬유성 바이오매스의 이용 방법은 크게 물리화학적 처리방법 과 효소처리(생물학적처리)로 나뉘어 지며, 효소적 처리는 친 환경처리 방법으로 알려져 있다 [8,12]. 섬유성 바이오매스를 구성하는 성분들은 섬유소 분해 효율에 있어 상호간에 영향을 미치는 것으로 알려져 있다 [1,9,15]. 따라서 기질의 종류에 따 라서 다양한 효소들의 상호관계의 이해는 섬유성 바이오매스 의 분해 효율성 향상에 중요한 역할을 할 수 있다.…”

“…이러한 단점을 보완하기 위하여 full factorial design 방법이 적용되었 으며, 이 방법은 요인들의 주효과와 상호작용을 알 수 있는 장점이 있는 반면, 요인분석을 위하여 수많은 실험이 요구되 는 단점이 있다 [5] C, H and X mean cellulase (1 mg/ml), hemicellulase (1 mg/ml) and xylanase (1 mg/ml), respectively 2 SE, E, R and I mean total standard error, effect of enzymes, effect of rice straw content and interaction of E and R, respectively Different superscripts in same rice straw content mean significantly different (p<0.05). [1,9]. 또한 xylanase도 cellulase의 활성 저해요인으로 알려진 xylooligomer를 제거하 여 cellulase의 작용을 향상시킨다고 보고되었다 [15].…”