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Fermentative hydrogen production from agroindustrial lignocellulosic substrates.

Reginatto V, Antônio RV - Braz. J. Microbiol. (2015)

Bottom Line: The average H2 production from pretreated material is 3.17 ± 1.79 mmol of H2/g of substrate, which is approximately 50% higher compared with the average yield achieved using untreated materials (2.17 ± 1.84 mmol of H2/g of substrate).Biological pretreatment affords the highest average yield 4.54 ± 1.78 mmol of H2/g of substrate compared with the acid and basic pretreatment - average yields of 2.94 ± 1.85 and 2.41 ± 1.52 mmol of H2/g of substrate, respectively.The average H2 yield from hydrolysates, obtained from a pretreatment step and enzymatic hydrolysis (3.78 ± 1.92 mmol of H2/g), was lower compared with the yield of substrates pretreated by biological methods only, demonstrating that it is important to avoid the formation of inhibitors generated by chemical pretreatments.

View Article: PubMed Central - PubMed

Affiliation: Universidade de São Paulo, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil, Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.

ABSTRACT
To achieve economically competitive biological hydrogen production, it is crucial to consider inexpensive materials such as lignocellulosic substrate residues derived from agroindustrial activities. It is possible to use (1) lignocellulosic materials without any type of pretreatment, (2) lignocellulosic materials after a pretreatment step, and (3) lignocellulosic materials hydrolysates originating from a pretreatment step followed by enzymatic hydrolysis. According to the current literature data on fermentative H2 production presented in this review, thermophilic conditions produce H2 in yields approximately 75% higher than those obtained in mesophilic conditions using untreated lignocellulosic substrates. The average H2 production from pretreated material is 3.17 ± 1.79 mmol of H2/g of substrate, which is approximately 50% higher compared with the average yield achieved using untreated materials (2.17 ± 1.84 mmol of H2/g of substrate). Biological pretreatment affords the highest average yield 4.54 ± 1.78 mmol of H2/g of substrate compared with the acid and basic pretreatment - average yields of 2.94 ± 1.85 and 2.41 ± 1.52 mmol of H2/g of substrate, respectively. The average H2 yield from hydrolysates, obtained from a pretreatment step and enzymatic hydrolysis (3.78 ± 1.92 mmol of H2/g), was lower compared with the yield of substrates pretreated by biological methods only, demonstrating that it is important to avoid the formation of inhibitors generated by chemical pretreatments. Based on this review, exploring other microorganisms and optimizing the pretreatment and hydrolysis conditions can make the use of lignocellulosic substrates a sustainable way to produce H2.

No MeSH data available.


Schematic view of the major metabolic pathways that lead to theproduction of H2, CO2, and acetate from thecarbohydrate components obtained from the hydrolysis of lignocellulosicmaterials. EMP, Embden-Meyerhoff-Parma; Fd, oxidized ferredoxin;FdH2, reduced ferredoxin; Hyd, hydrogenase; PFOR, pyruvate:ferredoxin oxyreductase; PP, pentose phosphate; XI, xylose isomerase; XK,xylulokinase. The dashed arrows indicate multisteps of a metabolicpathway.
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f01: Schematic view of the major metabolic pathways that lead to theproduction of H2, CO2, and acetate from thecarbohydrate components obtained from the hydrolysis of lignocellulosicmaterials. EMP, Embden-Meyerhoff-Parma; Fd, oxidized ferredoxin;FdH2, reduced ferredoxin; Hyd, hydrogenase; PFOR, pyruvate:ferredoxin oxyreductase; PP, pentose phosphate; XI, xylose isomerase; XK,xylulokinase. The dashed arrows indicate multisteps of a metabolicpathway.

Mentions: Figure 1 shows the main steps of the metabolicpathways and enzymes leading to H2 production throughout glucose andxylose fermentation performed by anaerobic microorganisms. The figure shows that theenzyme xylose isomerase (XI) catalyzes the isomerization of xylose to xylulose. Thelatter is then phosphorylated by xylulokinase (XK), to afford xylulose-5-phosphate,one of the intermediates of the pentose phosphate (PP) pathway. Through theactivities of epimerase, isomerase, transketolases, and transaldolases, enzymes ofthe PP pathway, xylulose-5-phosphate is converted to fructose-6-phosphate andglyceraldehyde-3-phosphate. Both of these compounds are intermediates of the EMPpathway, through which they undergo conversion to pyruvate. The supposed activitiesof pyruvate, ferredoxin oxyreductase (PFOR) and ferredoxin-dependent hydrogenase(Hyd) will produce H2, CO2, and acetate.


Fermentative hydrogen production from agroindustrial lignocellulosic substrates.

Reginatto V, Antônio RV - Braz. J. Microbiol. (2015)

Schematic view of the major metabolic pathways that lead to theproduction of H2, CO2, and acetate from thecarbohydrate components obtained from the hydrolysis of lignocellulosicmaterials. EMP, Embden-Meyerhoff-Parma; Fd, oxidized ferredoxin;FdH2, reduced ferredoxin; Hyd, hydrogenase; PFOR, pyruvate:ferredoxin oxyreductase; PP, pentose phosphate; XI, xylose isomerase; XK,xylulokinase. The dashed arrows indicate multisteps of a metabolicpathway.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507523&req=5

f01: Schematic view of the major metabolic pathways that lead to theproduction of H2, CO2, and acetate from thecarbohydrate components obtained from the hydrolysis of lignocellulosicmaterials. EMP, Embden-Meyerhoff-Parma; Fd, oxidized ferredoxin;FdH2, reduced ferredoxin; Hyd, hydrogenase; PFOR, pyruvate:ferredoxin oxyreductase; PP, pentose phosphate; XI, xylose isomerase; XK,xylulokinase. The dashed arrows indicate multisteps of a metabolicpathway.
Mentions: Figure 1 shows the main steps of the metabolicpathways and enzymes leading to H2 production throughout glucose andxylose fermentation performed by anaerobic microorganisms. The figure shows that theenzyme xylose isomerase (XI) catalyzes the isomerization of xylose to xylulose. Thelatter is then phosphorylated by xylulokinase (XK), to afford xylulose-5-phosphate,one of the intermediates of the pentose phosphate (PP) pathway. Through theactivities of epimerase, isomerase, transketolases, and transaldolases, enzymes ofthe PP pathway, xylulose-5-phosphate is converted to fructose-6-phosphate andglyceraldehyde-3-phosphate. Both of these compounds are intermediates of the EMPpathway, through which they undergo conversion to pyruvate. The supposed activitiesof pyruvate, ferredoxin oxyreductase (PFOR) and ferredoxin-dependent hydrogenase(Hyd) will produce H2, CO2, and acetate.

Bottom Line: The average H2 production from pretreated material is 3.17 ± 1.79 mmol of H2/g of substrate, which is approximately 50% higher compared with the average yield achieved using untreated materials (2.17 ± 1.84 mmol of H2/g of substrate).Biological pretreatment affords the highest average yield 4.54 ± 1.78 mmol of H2/g of substrate compared with the acid and basic pretreatment - average yields of 2.94 ± 1.85 and 2.41 ± 1.52 mmol of H2/g of substrate, respectively.The average H2 yield from hydrolysates, obtained from a pretreatment step and enzymatic hydrolysis (3.78 ± 1.92 mmol of H2/g), was lower compared with the yield of substrates pretreated by biological methods only, demonstrating that it is important to avoid the formation of inhibitors generated by chemical pretreatments.

View Article: PubMed Central - PubMed

Affiliation: Universidade de São Paulo, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil, Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.

ABSTRACT
To achieve economically competitive biological hydrogen production, it is crucial to consider inexpensive materials such as lignocellulosic substrate residues derived from agroindustrial activities. It is possible to use (1) lignocellulosic materials without any type of pretreatment, (2) lignocellulosic materials after a pretreatment step, and (3) lignocellulosic materials hydrolysates originating from a pretreatment step followed by enzymatic hydrolysis. According to the current literature data on fermentative H2 production presented in this review, thermophilic conditions produce H2 in yields approximately 75% higher than those obtained in mesophilic conditions using untreated lignocellulosic substrates. The average H2 production from pretreated material is 3.17 ± 1.79 mmol of H2/g of substrate, which is approximately 50% higher compared with the average yield achieved using untreated materials (2.17 ± 1.84 mmol of H2/g of substrate). Biological pretreatment affords the highest average yield 4.54 ± 1.78 mmol of H2/g of substrate compared with the acid and basic pretreatment - average yields of 2.94 ± 1.85 and 2.41 ± 1.52 mmol of H2/g of substrate, respectively. The average H2 yield from hydrolysates, obtained from a pretreatment step and enzymatic hydrolysis (3.78 ± 1.92 mmol of H2/g), was lower compared with the yield of substrates pretreated by biological methods only, demonstrating that it is important to avoid the formation of inhibitors generated by chemical pretreatments. Based on this review, exploring other microorganisms and optimizing the pretreatment and hydrolysis conditions can make the use of lignocellulosic substrates a sustainable way to produce H2.

No MeSH data available.