Switchgrass for bioethanol and other value-added applications: A review

Keshwani, Deepak R.; Ji, Cheng

doi:10.1016/j.biortech.2008.09.035

Cited by 371 publications

(216 citation statements)

References 119 publications

Supporting

Mentioning

202

Contrasting

Unclassified

Order By: Relevance

“…Keshwani and Cheng [16] reported that adapted switchgrass varieties should produce between 5000 to 6000 L of ethanol ha −1 , higher than Schmer et al's [29] estimate of 2000 to 4000 L ha −1 . These switchgrass TEP values contrast with 4000 L ha −1 for corn starch and 2000 L ha −1 for corn stover from agricultural soils [16].…”

Section: Experiment1: Theoretical Ethanol Yield and Productionmentioning

confidence: 79%

Switchgrass Biofuel Production on Reclaimed Surface Mines: II. Feedstock Quality and Theoretical Ethanol Production

et al. 2015

View full text Add to dashboard Cite

Switchgrass (Panicum virgatum L.), a warmseason perennial grass, is an important bioenergy crop candidate because it produces high biomass yields on marginal lands and on reclaimed surface mined sites. In companion studies, dry matter (DM) yields for Cave-inRock, Shawnee, and Carthage cultivars varied from 4.2 to 13.0 Mg ha −1 averaged over 6 years at the reclaimed Hampshire site, and fertilization increased yields of Cave-in-Rock at Black Castle and Coal Mac sites from 0.3 to 2 Mg ha −1 during the first 3 years. The objective of these experiments was to compare the impacts of cultivar and soil amendments on biomass quality and theoretical ethanol production of switchgrass grown on surface mines with differing soil characteristics. Biomass quality was determined for fiber, ash, lignin, digestibility, and carbohydrate contents via near-infrared reflectance spectroscopy, and carbohydrates were used to calculate theoretical ethanol yield (TEY; L Mg −1 ) and multiplied by biomass yield to calculate theoretical ethanol production (TEP; L ha −1 ). Cultivars at the Hampshire site did not differ in TEY and ranged from 426 to 457 L Mg −1 . Theoretical ethanol production from Cave-in-Rock at Hampshire was 7350 L ha −1 , which was higher than other cultivars because of its greater biomass production. This TEP was higher than in other studies which predicted 4000 to 5000 L ha −1 . At the Black Castle and Coal Mac sites, fertilizer applications slightly affected biomass quality of switchgrass and TEY, but provided greater TEP as a function of increased yield. Similar to other findings, total switchgrass biomass production has more impact than compositional differences on TEP, so maximizing biomass production is critical for maximizing potential biofuel production. With appropriate soil substrates, fertilization, planning, and management, large areas of reclaimed surface mines can be converted to switchgrass stands to produce high biomass quality and yields to support a bioethanol industry.

show abstract

Section: Experiment1: Theoretical Ethanol Yield and Productionmentioning

confidence: 79%

Switchgrass Biofuel Production on Reclaimed Surface Mines: II. Feedstock Quality and Theoretical Ethanol Production

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Switchgrass is a dedicated perennial herbaceous feedstock that is attractive for the production of biofuels and specialty chemicals (Keshwani and Cheng, 2009; Kwit et al ., 2014). It is a native perennial plant with good yields (3‐8 tons/acre) and can be grown in a range of North American ecosystems (U.S. Department of Energy et al ., 2016).…”

Section: Introductionmentioning

confidence: 99%

Transgenic switchgrass (Panicum virgatum L.) targeted for reduced recalcitrance to bioconversion: a 2‐year comparative analysis of field‐grown lines modified for target gene or genetic element expression

Dumitrache

Natzke

Rodríguez

et al. 2017

Plant Biotechnology Journal

View full text Add to dashboard Cite

SummaryTransgenic Panicum virgatum L. silencing (KD) or overexpressing (OE) specific genes or a small RNA (GAUT4‐KD, miRNA156‐OE, MYB4‐OE,COMT‐KD and FPGS‐KD) was grown in the field and aerial tissue analysed for biofuel production traits. Clones representing independent transgenic lines were established and senesced tissue was sampled after year 1 and 2 growth cycles. Biomass was analysed for wall sugars, recalcitrance to enzymatic digestibility and biofuel production using separate hydrolysis and fermentation. No correlation was found between plant carbohydrate content and biofuel production pointing to overriding structural and compositional elements that influence recalcitrance. Biomass yields were greater for all lines in the second year as plants establish in the field and standard amounts of biomass analysed from each line had more glucan, xylan and less ethanol (g/g basis) in the second‐ versus the first‐year samples, pointing to a broad increase in tissue recalcitrance after regrowth from the perennial root. However, biomass from second‐year growth of transgenics targeted for wall modification, GAUT4‐KD,MYB4‐OE,COMT‐KD and FPGS‐KD, had increased carbohydrate and ethanol yields (up to 12% and 21%, respectively) compared with control samples. The parental plant lines were found to have a significant impact on recalcitrance which can be exploited in future strategies. This summarizes progress towards generating next‐generation bio‐feedstocks with improved properties for microbial and enzymatic deconstruction, while providing a comprehensive quantitative analysis for the bioconversion of multiple plant lines in five transgenic strategies.

show abstract

“…First-generation biofuels produced from food crops, such as corn, are limited by cost and competition with food supply (6,7). Switchgrass is a perennial grass native to North America, and its high productivity on marginal farmlands and low agricultural input requirements make it an attractive feedstock for the production of biofuels and biochemicals (8). A yield of 36.7 Mg·ha −1 was achieved in field trials in Oklahoma (9), and switchgrass has the potential to produce 500% or more energy than is used for its cultivation (10).…”

mentioning

confidence: 99%

Direct conversion of plant biomass to ethanol by engineered Caldicellulosiruptor bescii

Chung

Cha

Guss

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

201

171

View full text Add to dashboard Cite

Ethanol is the most widely used renewable transportation biofuel in the United States, with the production of 13.3 billion gallons in 2012 [John UM (2013) Contribution of the Ethanol Industry to the Economy of the United States]. Despite considerable effort to produce fuels from lignocellulosic biomass, chemical pretreatment and the addition of saccharolytic enzymes before microbial bioconversion remain economic barriers to industrial deployment [Lynd LR, et al. (2008) Nat Biotechnol 26(2):169-172]. We began with the thermophilic, anaerobic, cellulolytic bacterium Caldicellulosiruptor bescii, which efficiently uses unpretreated biomass, and engineered it to produce ethanol. Here we report the direct conversion of switchgrass, a nonfood, renewable feedstock, to ethanol without conventional pretreatment of the biomass. This process was accomplished by deletion of lactate dehydrogenase and heterologous expression of a Clostridium thermocellum bifunctional acetaldehyde/alcohol dehydrogenase. Whereas wild-type C. bescii lacks the ability to make ethanol, 70% of the fermentation products in the engineered strain were ethanol [12.8 mM ethanol directly from 2% (wt/vol) switchgrass, a real-world substrate] with decreased production of acetate by 38% compared with wild-type. Direct conversion of biomass to ethanol represents a new paradigm for consolidated bioprocessing, offering the potential for carbon neutral, cost-effective, sustainable fuel production. metabolic engineering | bioenergy and thermophiles

show abstract

Switchgrass for bioethanol and other value-added applications: A review

Cited by 371 publications

References 119 publications

Switchgrass Biofuel Production on Reclaimed Surface Mines: II. Feedstock Quality and Theoretical Ethanol Production

Switchgrass Biofuel Production on Reclaimed Surface Mines: II. Feedstock Quality and Theoretical Ethanol Production

Transgenic switchgrass (Panicum virgatum L.) targeted for reduced recalcitrance to bioconversion: a 2‐year comparative analysis of field‐grown lines modified for target gene or genetic element expression

Direct conversion of plant biomass to ethanol by engineered Caldicellulosiruptor bescii

Contact Info

Product

Resources

About