Process optimization to convert forage and sweet sorghum bagasse to ethanol based on ammonia fiber expansion (AFEX) pretreatment

Li, Bing Zhi; Balan, Venkatesh; Yuan, Ying; Dale, Bruce E.

doi:10.1016/j.biortech.2009.09.044

Cited by 212 publications

(88 citation statements)

References 33 publications

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“…Sweet sorghum (Sorghum bicolor (L.) Moench) is a high-yielding sugar crop characterized by its adaptability to harsh growth conditions, such as its comparatively high tolerance to drought, water logging, salinity, and alkalinity (Corredor et al 2009;Li et al 2010). As a complementary feedstock to sugarcane, sweet sorghum offers the existing sugar-based biofuels industry a flexible, low-cost crop that can be collected from existing harvests and can be processed with the current infrastructure, or with new conversion technologies, to other liquid transportation fuels or bioproducts (Spencer 2009).…”

Section: Introductionmentioning

confidence: 99%

Fractional Separation and Structural Features of Hemicelluloses From Sweet Sorghum Leaves

Peng¹,

Bian²,

Peng³

et al. 2012

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Six hemicellulosic samples were isolated from cell wall material of dewaxed sweet sorghum (Sorghum bicolor (L.) Moench) leaves by sequential extractions with distilled water, alkali, and organic alkali solvent. The samples were treated with water, 1% NaOH, and 60% ethanol. The organic alkali samples were treated with 1%, 3%, 5%, and 8% NaOH, which yielded 8.3%, 5.4%, 1.0%, 5.6%, 2.5%, and 4.9% hemicelluloses based on the dry initial sweet sorghum leaves, respectively, and resulted in a total release of 81% of all hemicelluloses originally present in the cell wall. The results indicated that water-soluble hemicelluloses contained noticeable amounts of glucose, arabinose, galactose, and xylose, and had a relatively lower molecular weight (17300 g/mol). The four alkali-soluble hemicellulosic fractions, rich in xylose, were more linear, and had higher molecular weights (48500-128000 g/mol) than those of the alkali organic-soluble hemicellulosic fraction. With an increase of NaOH concentration from 1% to 8%, the ratio of arabinose to xylose decreased from 0.29 to 0.01, which implied that the hemicelluloses obtained by the higher concentration of alkali appeared to be more linear. Based on the sugar analysis, Fourier transform infrared (FT-IR), and nuclear magnetic resonance (NMR) results, 4-O-methylglucuronoarabinoxylans were the major constituents of the hemicellulosic polymers.

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Section: Introductionmentioning

confidence: 99%

Fractional Separation and Structural Features of Hemicelluloses From Sweet Sorghum Leaves

Peng¹,

Bian²,

Peng³

et al. 2012

BioResources

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“…Aqueous ammonia has been widely used for the pretreatment of lignocelluloses and is recyclable due to its volatility. As previous studies have reported, ammonia pretreatment allows the retention of most of the cellulose and hemicellulose components while removing a portion of lignin and altering its structure (Kim et al 2003;Li et al 2010;Rémond et al 2010;Gao et al 2012). An aqueous ammonia pretreatment can delignify lignocellulose by disrupting the C-O-C bonds in lignin as well as the ester bonds in the LCC (Hsu et al 2010;Alvira et al 2010;Balat 2011;Nguyen et al 2010).…”

Section: Introductionmentioning

confidence: 96%

Comparison of the Delignifiability and Hydrolysability of Wheat Straw and Corn Stover in Aqueous Ammonia Pretreatment

Jia¹,

Sun²,

Ge³

et al. 2013

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The impact of an aqueous ammonia pretreatment on the structural properties, delignifiability, and hydrolysability of wheat straw and corn stover was investigated. The results showed that the aqueous ammonia pretreatment had an excellent delignification ability and that the corn stover exhibited higher susceptibility to an aqueous ammonia attack than wheat straw. In total, 35.6% and 70.0% of the lignin in wheat straw and corn stover were removed, respectively, by the aqueous ammonia pretreatment at 75 ºC with 21% ammonia and a solid:liquid ratio of 1:10 for 20 h. Both lignin and polysaccharides in the corn stover exhibited higher susceptibility to aqueous ammonia than those in wheat straw. In addition, the hydrolysability of corn stover was more susceptible to aqueous ammonia than it was to wheat straw. A chemical structure analysis of different substrates showed that the aqueous ammonia pretreatment removed lignin, broke ester bonds between lignin and hemicelluloses, increased the specific surface area and crystallinity index, and, finally, enhanced the hydrolysis yield.

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“…Xylose is the second most abundant fermentable monosaccharide released from lignocelluloses biomass [1][2][3]. Efficient xylose utilization in the lignocellulosic hydrolysate is an important issue for economic bioconversion of lignocelluloses [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…To achieve high product titer, solid-tosolid pretreatments have been preferred to facilitate fermentation with high solid loading of feedstock [8][9][10]. During such pretreatments, xylan (xylose) and glucan (glucose) are usually in the same pot during fermentation [1,[11][12][13]. Simultaneous xylose and glucose utilization would be an efficient approach for lignocellulose bioconversion.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Simultaneous Xylose and Glucose Utilization by Regulating ZWF1 and PGI1 in Saccharomyces Cerevisiae

Liu

et al. 2017

Trans. Tianjin Univ.

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Xylose utilization is one of the key issues in lignocellulose bioconversion. Because of glucose repression, in most engineered yeast with heterogeneous xylose metabolic pathway, xylose is not consumed until glucose is completely utilized. Although simultaneous glucose and xylose utilization have been achieved in yeast by RPE1 deletion, we regulated ZWF1 and PGI1 transcription to improve simultaneous xylose and glucose utilization by controlling the metabolic flux from glucose into the PP pathway. Xylose and glucose consumption increased by approximately 80 and 72%, respectively, whereas ZWF1 was overexpressed by multi-copy plasmids with a strong transcriptional promoter. PGI1 expression was knocked down by promoter replacement; the glucose and xylose metabolism increased when PGI1p was replaced by weak promoters, SSA1p and PDA1p. ZWF1 overexpression decreased while PGI1 down-regulation increased the ethanol yield to some extent in the recombinant strains.

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Process optimization to convert forage and sweet sorghum bagasse to ethanol based on ammonia fiber expansion (AFEX) pretreatment

Cited by 212 publications

References 33 publications

Fractional Separation and Structural Features of Hemicelluloses From Sweet Sorghum Leaves

Fractional Separation and Structural Features of Hemicelluloses From Sweet Sorghum Leaves

Comparison of the Delignifiability and Hydrolysability of Wheat Straw and Corn Stover in Aqueous Ammonia Pretreatment

Enhancement of Simultaneous Xylose and Glucose Utilization by Regulating ZWF1 and PGI1 in Saccharomyces Cerevisiae

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