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Doubling Power Output of Starch Biobattery Treated by the Most Thermostable Isoamylase from an Archaeon Sulfolobus tokodaii.

Cheng K, Zhang F, Sun F, Chen H, Percival Zhang YH - Sci Rep (2015)

Bottom Line: This enzyme was characterized and required Mg(2+) as an activator.This enzyme was the most stable isoamylase reported with a half lifetime of 200 min at 90 (o)C in the presence of 0.5 mM MgCl2, suitable for simultaneous starch gelatinization and isoamylase hydrolysis.The cuvett-based air-breathing biobattery powered by isoamylase-treated starch exhibited nearly doubled power outputs than that powered by the same concentration starch solution, suggesting more glucose 1-phosphate generated.

View Article: PubMed Central - PubMed

Affiliation: College of Life Sciences, Henan Agricultural University, 95 Wenhua Road, Zhengzhou, 450002, China.

ABSTRACT
Biobattery, a kind of enzymatic fuel cells, can convert organic compounds (e.g., glucose, starch) to electricity in a closed system without moving parts. Inspired by natural starch metabolism catalyzed by starch phosphorylase, isoamylase is essential to debranch alpha-1,6-glycosidic bonds of starch, yielding linear amylodextrin - the best fuel for sugar-powered biobattery. However, there is no thermostable isoamylase stable enough for simultaneous starch gelatinization and enzymatic hydrolysis, different from the case of thermostable alpha-amylase. A putative isoamylase gene was mined from megagenomic database. The open reading frame ST0928 from a hyperthermophilic archaeron Sulfolobus tokodaii was cloned and expressed in E. coli. The recombinant protein was easily purified by heat precipitation at 80 (o)C for 30 min. This enzyme was characterized and required Mg(2+) as an activator. This enzyme was the most stable isoamylase reported with a half lifetime of 200 min at 90 (o)C in the presence of 0.5 mM MgCl2, suitable for simultaneous starch gelatinization and isoamylase hydrolysis. The cuvett-based air-breathing biobattery powered by isoamylase-treated starch exhibited nearly doubled power outputs than that powered by the same concentration starch solution, suggesting more glucose 1-phosphate generated.

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Related in: MedlinePlus

The stability profile of isoamylase in the presence of 0.5 mM MgCl2, 0.5 mM CaCl2 or the absence of bivalent metal ions at 90 °C.The buffer was 40 mM acetate buffer (pH 5.5) containing 7.5 μg/ml isoamylase.
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f5: The stability profile of isoamylase in the presence of 0.5 mM MgCl2, 0.5 mM CaCl2 or the absence of bivalent metal ions at 90 °C.The buffer was 40 mM acetate buffer (pH 5.5) containing 7.5 μg/ml isoamylase.

Mentions: This isoamylase in the acetate buffer (pH 5.5) were very stable at temperatures of 60–80 oC, less than 1% activity losses for 1 h, and remained 87% activity after 1 h incubation of 90 oC. Surprisingly, this enzyme was more stable in the presence of 5 MgCl2 than the absence of bivalent ions (Fig. 5). The addition of MgCl2 resulted in a half lifetime of 200 min at 90 oC. In contrast, CaCl2 decreased this enzyme stability greatly, resulting in a half lifetime of 35 min.


Doubling Power Output of Starch Biobattery Treated by the Most Thermostable Isoamylase from an Archaeon Sulfolobus tokodaii.

Cheng K, Zhang F, Sun F, Chen H, Percival Zhang YH - Sci Rep (2015)

The stability profile of isoamylase in the presence of 0.5 mM MgCl2, 0.5 mM CaCl2 or the absence of bivalent metal ions at 90 °C.The buffer was 40 mM acetate buffer (pH 5.5) containing 7.5 μg/ml isoamylase.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542469&req=5

f5: The stability profile of isoamylase in the presence of 0.5 mM MgCl2, 0.5 mM CaCl2 or the absence of bivalent metal ions at 90 °C.The buffer was 40 mM acetate buffer (pH 5.5) containing 7.5 μg/ml isoamylase.
Mentions: This isoamylase in the acetate buffer (pH 5.5) were very stable at temperatures of 60–80 oC, less than 1% activity losses for 1 h, and remained 87% activity after 1 h incubation of 90 oC. Surprisingly, this enzyme was more stable in the presence of 5 MgCl2 than the absence of bivalent ions (Fig. 5). The addition of MgCl2 resulted in a half lifetime of 200 min at 90 oC. In contrast, CaCl2 decreased this enzyme stability greatly, resulting in a half lifetime of 35 min.

Bottom Line: This enzyme was characterized and required Mg(2+) as an activator.This enzyme was the most stable isoamylase reported with a half lifetime of 200 min at 90 (o)C in the presence of 0.5 mM MgCl2, suitable for simultaneous starch gelatinization and isoamylase hydrolysis.The cuvett-based air-breathing biobattery powered by isoamylase-treated starch exhibited nearly doubled power outputs than that powered by the same concentration starch solution, suggesting more glucose 1-phosphate generated.

View Article: PubMed Central - PubMed

Affiliation: College of Life Sciences, Henan Agricultural University, 95 Wenhua Road, Zhengzhou, 450002, China.

ABSTRACT
Biobattery, a kind of enzymatic fuel cells, can convert organic compounds (e.g., glucose, starch) to electricity in a closed system without moving parts. Inspired by natural starch metabolism catalyzed by starch phosphorylase, isoamylase is essential to debranch alpha-1,6-glycosidic bonds of starch, yielding linear amylodextrin - the best fuel for sugar-powered biobattery. However, there is no thermostable isoamylase stable enough for simultaneous starch gelatinization and enzymatic hydrolysis, different from the case of thermostable alpha-amylase. A putative isoamylase gene was mined from megagenomic database. The open reading frame ST0928 from a hyperthermophilic archaeron Sulfolobus tokodaii was cloned and expressed in E. coli. The recombinant protein was easily purified by heat precipitation at 80 (o)C for 30 min. This enzyme was characterized and required Mg(2+) as an activator. This enzyme was the most stable isoamylase reported with a half lifetime of 200 min at 90 (o)C in the presence of 0.5 mM MgCl2, suitable for simultaneous starch gelatinization and isoamylase hydrolysis. The cuvett-based air-breathing biobattery powered by isoamylase-treated starch exhibited nearly doubled power outputs than that powered by the same concentration starch solution, suggesting more glucose 1-phosphate generated.

No MeSH data available.


Related in: MedlinePlus