Abstracts Category : Other

Prairie cordgrass as cellulosic ethanol feedstock and chemical hydrolysis with disk milling for pretreatment

by Sun Min Kim

Cellulosic ethanol plants have started operating at commercial scale; however, challenges related to feedstock supply and pretreatment efficiency still exist. To provide sufficient feedstock quantity, eleven natural populations of prairie cordgrass (Spartina pectinata L.) harvested in 2011 and 2012 were evaluated as a bioethanol feedstock. After dilute acid pretreatment and simultaneous saccharification and cofermentation (SScF), ethanol yields from prairie cordgrass reached 205 to 276 g/kg biomass and 1,379 to 3,446 kg/ha. These ethanol yields were comparable with those of switchgrass, corn stover and bagasse. To produce feedstocks in a sustainable manner, growing bioethanol feedstocks on marginal lands has been recommended. Ethanol production from prairie cordgrass and switchgrass grown on marginal lands were evaluated by performing dilute acid pretreatment and SScF. Plants grown on marginal lands had ethanol yields comparable to those of plants grown on optimal land.To increase enzyme accessibility to carbohydrates, hot water or dilute acid hydrolysis followed by disk milling was developed as a pretreatment method. Hot water or dilute acid pretreatment and disk milling acted synergistically to improve glucose and xylose yields by 89 and 134%, respectively, compared to hot water pretreatment alone. To take the combined pretreatment process one step closer to commercialization, disk milling was performed with commercially dilute acid pretreated corn stover. Effects of number of disk milling cycles and enzyme dosage on sugar yields were evaluated. Milling was more effective to improve glucose yields (by 70 to 120%), while enzyme dosage was more effective to improve xylose yields (by 37 to 57%). Compared to milling cycles and enzyme dosages, dilute acid pretreatment condition was the most important factor to increase final sugar yields.Advisors/Committee Members: Singh, Vijay (advisor), Singh, Vijay (Committee Chair), Rausch, Kent D (committee member), Tumbleson, M. E. (committee member), Jin, Yong-Su (committee member), Lee, DoKyoung (committee member), Basu, Rahul (committee member), Hensing, Marco (committee member), Dien, Bruce S (committee member).