Solid-State Fermentation of Cassava Roots Using Cellulolytic-Type Alkaliphilic Bacillus spp. Cultures to Modify the Cell Walls and Assist Starch Release.
Appl Biochem Biotechnol
; 191(4): 1395-1410, 2020 Aug.
Article
in En
| MEDLINE
| ID: mdl-32103472
ABSTRACT
To improve cassava starch extraction by wet milling, solid-state fermentation of ground roots using cellulolytic-type alkaliphilic Bacilli spp., Bacillus akibai, B. cellulosilyticus and B. hemicellulosilyticus was investigated. Enzyme assay and scanning electron microscopy indicated that Bacillus spp. production of extracellular cellulase and polygalacturonase caused the formation of micropores through the root parenchyma cell walls and exposed the embedded cellulosic network. Gas chromatography data of the cell wall constituent sugars remaining after fermentation and Fourier transform infrared data indicated that the Bacillus treatments reduced the levels of pectin and, hemicellulose and to lesser extent cellulose. Wide-angle X-ray scattering data indicated that the Bacillus spp. cell wall degrading enzymes had partially hydrolysed the amorphous fractions of the cell wall polysaccharides. All the Bacillus spp. treatments improved starch extraction by 17-23% compared to fermentation with endogenous microflora. B. cellulosilyticus was most effective in disintegration of large root particles and as result, released marginally the most starch, probably due to it having the highest cellulase activity. Solid-state fermentation using cellulolytic-type Bacillus spp. is, therefore, promising to technology to improve the efficiency of cassava wet milling cell wall disintegration and consequent starch yield without use of commercial cell wall degrading enzymes or polluting chemicals.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacillus
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Manihot
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Cell Wall
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Cellulose
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Plant Roots
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Fermentation
Language:
En
Journal:
Appl Biochem Biotechnol
Year:
2020
Document type:
Article
Affiliation country:
Sudáfrica
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
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EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
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US
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USA