Fate of free amino nitrogen during liquefaction and yeast fermentation of maize and sorghums differing in endosperm texture

Peralta-Contreras, Mayeli; Chuck‐Hernández, Cristina; Pérez‐Carrillo, Esther; Bando-Carranza, Gabriela; Vera-Garcia, Mariano; Gaxiola-Cuevas, Nallely; Tamayo-Limon, Ranses; Cárdenas-Torres, Feliznando Isidro; Serna‐Saldívar, Sergio O.

doi:10.1016/j.fbp.2012.08.007

Cited by 16 publications

(12 citation statements)

References 40 publications

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“…Nitrogen deficiencies have been reported as a major cause for a slow fermentation (Moreira et al 2011;Peralta-Contreras et al 2013). Fermentation requires an adequate supply of nitrogenous compounds to fuel yeast growth and proliferation.…”

Section: Figmentioning

confidence: 99%

“…Release of FAN during enzymatic breakdown of endosperm proteins provides a grain-specific source of amino nitrogen. Nitrogen deficiencies have been reported as a major cause for a slow fermentation (Moreira et al 2011;Peralta-Contreras et al 2013). Low FAN levels can be supplemented in the industrial fermentation process with a mix of amino acids and ammonium sulfate at the exponential phase of yeast growth, en-hancing fermentation rate and ethanol conversion efficiency but increasing commercial costs.…”

Section: Figmentioning

confidence: 99%

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Impacts of Kafirin Allelic Diversity, Starch Content, and Protein Digestibility on Ethanol Conversion Efficiency in Grain Sorghum

et al. 2014

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Cereal Chem. 91(3):218-227Seed protein and starch composition determine the efficiency of the fermentation process in the production of grain-based ethanol. Sorghum, a highly water-and nutrient-efficient plant, provides an alternative to fuel crops with greater irrigation and fertilizer requirements, such as maize. However, sorghum grain is generally less digestible because of extensive disulfide cross-linking among sulfur-rich storage proteins in the proteinstarch matrix. Thus, the fine structure and composition of the seed endosperm directly impact grain end use, including fermentation performance. To test the hypothesis that kafirin (prolamin) seed storage proteins specifically influence the efficiency of ethanol production from sorghum, 10 diverse genetic lines with allelic variation in the β-, γ-, and δ-kafirins, including three β-kafirin null mutants, were tested for ethanol yield and fermentation efficiency. Our selected lines showed wide variation in grain biochemical features, including total protein (9.96-16.47%), starch (65.52-74.29%), and free amino nitrogen (FAN) (32.84-73.51 mg/L). Total ethanol yield (ranging from 384 to 426 L/metric ton), was positively correlated to starch content (R 2 = 0.74), and there was a slight positive correlation between protein digestibility and ethanol yield (R 2 = 0.52). Increases in FAN content enhanced fermentation efficiency (R 2 = 0.65). The highest ethanol producer was elite staygreen breeding line B923296, and the line with the highest fermentation efficiency at the 72 h time point was inbred BT×623. A large-seeded genotype, KS115, carrying a novel γ-kafirin allele, was rich in FAN and exhibited excellent short-term fermentation efficiency at 85.68% at the 20 h time point. However, the overall ethanol yield from this line was comparatively low at 384 L/metric ton, because of insufficient starch, low digestibility, and high crude protein.Multivariate analysis indicated an association between the β-kafirin allele and variation in grain digestibility (P = 0.042) and FAN (P = 0.036), with subsequent effects on ethanol yield. Reversed-phase HPLC profiling of the alcohol-soluble kafirin protein fraction revealed diversity in protein content and composition across the lines, with similarities in peak distribution profiles among β-kafirin null mutants compared with normal lines.

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Section: Figmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Impacts of Kafirin Allelic Diversity, Starch Content, and Protein Digestibility on Ethanol Conversion Efficiency in Grain Sorghum

et al. 2014

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“…In bioethanol fermentation processes of sorghum and corn, the liberation of FAN was studied to assess the requirement for supplementation. The flour of red sorghum, corn and white sorghum showed a content of 63.3, 82.5 and 43.1 mg L −1 FAN respectively before the hydrolysis process . The level of FAN increased by proteolysis during 195 min of liquefaction and saccharification, so mashes contained 79.36, 101.67 and 65.93 mg L −1 FAN respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The flour of red sorghum, corn and white sorghum showed a content of 63.3, 82.5 and 43.1 mg L −1 FAN respectively before the hydrolysis process. 33 The level of FAN increased by proteolysis during 195 min of liquefaction and saccharification, so mashes contained 79.36, 101.67 and 65.93 mg L −1 FAN respectively. Therefore the utilization of these raw materials subjected to liquefaction and proteolysis did not require further nitrogen supplementation.…”

Section: Chemical Compositionmentioning

confidence: 95%

Whole unripe plantain (Musa paradisiaca L.) as raw material for bioethanol production

et al. 2019

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BACKGROUND The use of byproducts such as rejected plantain with final disposition problems and conversion processes with ‘green’ technologies are important research topics. Bioethanol production from crops with a high content of fermentable sugars is an alternative to that from traditional crops (corn and sugar cane). The aim of this work was to study the use of whole (peel and pulp) unripe plantain (WP) for bioethanol production. RESULTS Lab‐scale liquefaction and saccharification of both materials released mainly three carbohydrates, glucose (9.02 mg g−1), maltose (0.45 mg g−1) and xylose (0.25 mg g−1). The WP saccharification required the use of pectinase and cellulase because of the high amounts of pectin and cellulose associated with the peel. Fermentation for 11 h produced similar ethanol concentration for both samples, but at the end of fermentation (32 h), the ethanol production was higher in the WP (58.6 mL L−1) compared with the plantain pulp (PP) (45.5 mL L−1). The theoretical ethanol yield was lower with WP (67%) than with PP (90%). CONCLUSION WP can be an alternative raw material for bioethanol production. © 2019 Society of Chemical Industry

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“…Release of FAN during enzymatic breakdown of endosperm proteins provides a grainspecific source of amino nitrogen. Nitrogen deficiencies have been reported as a major cause for a slow fermentation (259,260). Low FAN levels can be supplemented in the industrial fermentation process with a mix of amino acids and ammonium sulphate at the exponential phase of yeast growth, enhancing fermentation rate and ethanol conversion efficiency, but increasing commercial costs.…”

Section: Free Amino Nitrogen (Fan) Impact On Fermentation Efficiencymentioning

confidence: 99%

Grain Proteomics of Sorghum: Improving Digestibility, Nutritional Quality and Starch Conversion to Ethanol

Cremer¹

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Sorghum is an important food staple in rural Asia, India and Africa and a major feedstock in developed countries. Originating in the semi-arid African savannah, sorghum is well adapted to drought prone environments and produces more biomass per unit water than maize. Extensive variability exists within the sorghum gene pool creating a diversity of plant forms with many commercial and industrial applications. Sorghum, provides an alternative to grain crops with greater irrigation and fertiliser requirements, such as maize, however, the grain is generally less digestible, especially upon cooking, due to extensive disulphide cross-linking among sulphur-rich storage proteins in the protein-starch matrix. This reduces the accessibility of proteolytic enzymes to starch, decreasing palatability and nutritional value, and resulting in the need for increased processing.The commercial value of cereals is largely determined by the chemistry of the protein-starch matrix.Located on the periphery of storage protein bodies, cysteine-rich β-and γ-kafirins prevent enzymatic access to internally positioned α-kafirins and to starch. The development of mutants is an efficient approach for studying genetic regulation of protein biosynthesis and compartmentalisation and shows how changes in protein profile affect the physical characteristics of the seed. An integrated proteomic approach was employed to characterise 28 sorghum lines with allelic variation at the kafirin loci, including three β-kafirin null mutants, in order to determine the effects of kafirin genetic diversity on the expression of storage proteins.High performance liquid chromatography (HPLC) and capillary electrophoresis were employed to profile water/salt-and alcohol-soluble protein fractions, revealing a wide range of diversity in protein content across the genotypes. Peak profiles were similar among β-kafirin null lines but different to normal lines, with a significant reduction in alcohol-soluble protein and the disappearance of a major set of protein peaks. The relative content of sequentially extracted soluble, insoluble and residual proteins was measured using RP-HPLC to evaluate the degree of crosslinking among storage proteins in the seed. High levels of insoluble and residual protein were associated with reduced digestibility.Gel-based separation of seed proteins and subsequent identification with tandem mass spectrometry identified a range of redox-active proteins affecting storage protein biochemistry. Multiple protein fractions were analysed across the β-kafirin null line QL12 and wild-type line 296B. The redox states of endosperm proteins, of which kafirins are a subset, have been shown to impact on quality traits in addition to the expression of proteins. Thioredoxin, active in the processing of storage v proteins at germination, has reported impacts on grain digestibility and was differentially expressed across the genotypes. A range of putative uncharacterised sorghum proteins regulating the folding and disulphide pairing of storage proteins ...

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Fate of free amino nitrogen during liquefaction and yeast fermentation of maize and sorghums differing in endosperm texture

Cited by 16 publications

References 40 publications

Impacts of Kafirin Allelic Diversity, Starch Content, and Protein Digestibility on Ethanol Conversion Efficiency in Grain Sorghum

Impacts of Kafirin Allelic Diversity, Starch Content, and Protein Digestibility on Ethanol Conversion Efficiency in Grain Sorghum

Whole unripe plantain (Musa paradisiaca L.) as raw material for bioethanol production

Grain Proteomics of Sorghum: Improving Digestibility, Nutritional Quality and Starch Conversion to Ethanol

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