Combined effect of pelleting and pretreatment on enzymatic hydrolysis of switchgrass

Rijal, Binod; Igathinathane, C.; Karki, Bishnu; Yu, Manlu; Pryor, Scott W.

doi:10.1016/j.biortech.2012.04.054

Cited by 53 publications

(33 citation statements)

References 22 publications

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“…Also, densification process has shown influence in the chemical composition of biomass [10][11][12], which is in turn related with the aforementioned quality attributes [11,13] and with the efficiency of the conversion process. Thus, reducing the variance of biomass chemical composition can lead to high quality densified biomass such as switchgrass, corn stover, and miscanthus, among others.…”

Section: Introductionmentioning

confidence: 99%

A Principal Component Analysis in Switchgrass Chemical Composition

Aboytes–Ojeda

Castillo-Villar

et al. 2016

Energies

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Abstract:In recent years, bioenergy has become a promising renewable energy source that can potentially reduce the greenhouse emissions and generate economic growth in rural areas. Gaining understanding and controlling biomass chemical composition contributes to an efficient biofuel generation. This paper presents a principal component analysis (PCA) that shows the influence and relevance of selected controllable factors over the chemical composition of switchgrass and, therefore, in the generation of biofuels. The study introduces the following factors: (1) storage days; (2) particle size; (3) wrap type; and (4) weight of the bale. Results show that all the aforementioned factors have an influence in the chemical composition. The number of days that bales have been stored was the most significant factor regarding changes in chemical components due to its effect over principal components 1 and 2 (PC1 and PC2, approximately 80% of the total variance). The storage days are followed by the particle size, the weight of the bale and the type of wrap utilized to enclose the bale. An increment in the number of days (from 75-150 days to 225 days) in storage decreases the percentage of carbohydrates by −1.03% while content of ash increases by 6.56%.Keywords: lignocellulosic biomass; principal component analysis; statistical hypothesis; bioenergy; switchgrass BackgroundBiofuel production is a promising alternative source of energy which provides advantages such as displacement of fossil-based fuels, reduction of greenhouse gas emissions, among others [1]. Biofuels can be classified according to the type of biomass utilized as follows: (1) first-generation biofuels are produced from organic sources commonly used as food for human consumption (e.g., sorghum, corn, among others); (2) second-generation biofuels are obtained from a wide range of non-food sources such as agricultural and forest residues, energy crops, and municipal solid waste; and (3) third-generation biofuels commonly refer to biofuels produced from algae [2]. This paper focuses on second-generation biofuels using a type of energy crop (i.e., switchgrass). The production of second-generation biofuels involves activities like harvesting, extracting, transporting and feedstock handling that can be enhanced to improve the biofuel supply chain performance [3,4]. Feedstock logistics play a relevant role in the optimization of the whole supply chain. Identifying factors in logistics operations that affect feedstock properties and its quality helps to improve the production of reliable biofuels.

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Section: Introductionmentioning

confidence: 99%

A Principal Component Analysis in Switchgrass Chemical Composition

Aboytes–Ojeda

Castillo-Villar

et al. 2016

Energies

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“…Karki et al [4] reported on the enzymatic hydrolysis of mixtures of switchgrass and tall wheatgrass following dilute-acid and aqueous ammonia pretreatments. Switchgrass and tall wheatgrass were similar in composition before and after dilute-acid pretreatment, although tall wheatgrass had significantly higher glucose yields from enzymatic hydrolysis.…”

Section: Introduction/backgroundmentioning

confidence: 99%

“…Rijal et al [4] showed that either pelleting or milling to a fine powder improved sugar release after pretreatment with either dilute acid (DA) or soaking in aqueous ammonia (SAA) followed by enzymatic hydrolysis. Pelletization of softwoods did not result in significant loss of hemicellulose and has been shown to produce a cellulosic substrate that is readily hydrolysable following steam pretreatment [5].…”

Section: Introduction/backgroundmentioning

confidence: 99%

The Effect of Biomass Densification on Structural Sugar Release and Yield in Biofuel Feedstock and Feedstock Blends

et al. 2017

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In this work, we examined the behavior of feedstock blends and the effect of a specific feedstock densification strategy (pelleting) on the release and yield of structural carbohydrates in a laboratory-scale dilute acid pretreatment (PT) and enzymatic hydrolysis (EH) assay. We report overall carbohydrate release and yield from the two-stage PT-EH assay for five single feedstocks (two corn stovers, miscanthus, switchgrass, and hybrid poplar) and three feedstock blends (corn stover-switchgrass, corn stover-switchgrass-miscanthus, and corn stover-switchgrass-hybrid poplar). We first examined the experimental results over time to establish the robustness of the PT-EH assay, which limits the precision of the experimental results. The use of two different control samples in the assay enabled us to identify (and correct for) a small bias in the EH portion of the combined assay for some runs. We then examined the effect of variable pretreatment reaction conditions (residence time, acid loading, and reactor temperature) on the conversion of a single feedstock (single-pass corn stover, CS-SP) in order to establish the range of pretreatment reaction conditions likely to provide optimal conversion data. Finally, we applied the assay to the 16 materials (8 feedstocks in 2 formats, loose and pelleted) over a more limited range of pretreatment experimental conditions. The four herbaceous feedstocks behaved similarly, while the hybrid poplar feedstock required higher pretreatment temperatures for optimal results. As expected, the yield data for three blended feedstocks were the average of the yield data for the individual feedstocks. The pelleting process appears to provide a slightly positive effect on overall total sugar yield.

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“…However, wheat straw is a lignocellulosic substrate, its main components are cellulose (between 40 and 50%), followed by hemicelluloses (31-43%) and lignin (6-10%) (Motte et al, 2014). This fact not only means a slow microbial degradation, but also a low bulk density which significantly increases its cost of handling, transportation (Theerarattananoon et al, 2012), and storage (Rijal et al, 2012).…”

Section: Introductionmentioning

confidence: 99%