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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #309195
Title: Conversion quality of napiergrass under different production practices

Author
item Anderson, William
item Dien, Bruce
item O Bryan, Patricia
item Cotta, Michael

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary: not required

Technical Abstract: Napiergrass (Pennisetum purpureum (L) Schum) is being developed as a bioenergy crop for production in southeastern United States. Efficient production practices are needed for the Southeast. Harvest intervals and fertilization practices have been evaluated for the past three years at Shellman, GA. Material from each replicated plot was tested for chemical composition, theoretical ethanol yields, and enzymatic sugar conversion efficiencies. The sample set consisted of material from the second year of established plots with three treatments. Low-moisture ammonium hydroxide (LMLA) was selected as the pretreatment strategy to prepare the biomass for enzymatic conversion. Pretreatment conditions were optimized for enzymatic sugar conversion using a central composite design and a single selected sample; these were: 20% g ammonium per g biomass, 110°C for 2 days. Biomass yields ranged from 29.2 – 38.7 Mg/ha dry matter, with the two-harvest system producing 10% higher biomass and 16% higher glucose yields after ammonia pretreatment. Samples were analyzed for soluble sugars, starch, structural carbohydrates, uronic acids, and Klason lignin. Glucan and total structural carbohydrate contents were 303 - 362 and 516 -610 g/kg, db, respectively. Acid Insoluble lignin contents were 123 – 182 g/kg, db. The enzyme formulation consisted of commercial celluases (5 FPU/g), xylanases (130 IU/g), and pectinase (15 IU xylanase/g). Glucose and xylose enzymatic conversion efficiencies were 91 – 109% glucose (only accounting for cellulose) and 67-77% xylose. The two harvest system resulted in more efficient cellulose conversion to glucose.