Thermostable liquefying ?-amylase fromBacillus amyloliquefaciens

Kochhar, Sunil; Dua, R. D.

doi:10.1007/bf01024438

Cited by 12 publications

(9 citation statements)

References 13 publications

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“…WN11 was growthassociated, reaching a maximum around 18 h. This may be an interesting property because it could allow harvesting of the enzyme in a shorter time. The mesophilic B. licheniformis and B. amyloliquefaciens, which are the main sources of commercial amylase at present, are reported to require a batch time of 48-72 h for optimum production (Roychudhury et al 1988;Kochhar and Dua 1990;Tonkova et al 1993).…”

Section: Discussionmentioning

confidence: 99%

“…The main source of commercial thermostable amylases is strains of the mesophilic bacteria, Bacillus licheniformis and B. amyloliquefaciens (Kelly et al 1990). The need for enzymes with improved properties has initiated a continuous search for micro-organisms producing novel amylases for industrial application (Ng and Kenealy 1986;Kochhar and Dua 1990). This is especially important as so far, only a very small percentage of the earth's microbial population has been properly examined (Cheetham 1987;Bull et al 1992).…”

Section: Introductionmentioning

confidence: 99%

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A highly thermostable amylase from a newly isolated thermophilicBacillussp. WN11

Mamo

Gashe²,

Gessesse

1999

Journal of Applied Microbiology

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A thermostable amylase-producing Bacillus sp. WN11 was isolated from Wondo Genet hot spring in Ethiopia. The enzyme had a temperature optimum of 75-80°C. Over 80% of its peak activity was in the pH range of 5-8, with an optimum at 5·5. Thermal stability of the enzyme at 105°C was higher with the addition of starch. The stabilizing effect of starch was concentrationdependent, showing better stability with increasing concentration of starch. At liquefying temperature (105°C), addition of Ca 2+ did not result in further improvement of the stabilizing effect of starch. This indicates that in the presence of starch, WN11 amylase does not require Ca 2+ as a stabilizer at liquefying temperatures as high as 105°C.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A highly thermostable amylase from a newly isolated thermophilicBacillussp. WN11

Mamo

Gashe²,

Gessesse

1999

Journal of Applied Microbiology

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“…Proteins in thin stillage experience temperatures >100°C during processing, so the concentration of corn proteins in thin stillage with an isoelectric point of pH 4.8 is probably low. Thermostable α-amylase enzymes from Bacillus amyloliquefaciens and B. licheniformis, which are commonly used in DG processes, have reported isoelectric points of pH 6.25 and 6.5, respectively (Kochhar and Dua 1990;Maasen 1991;Power 2003). Previous studies have reported isoelectric points of glucoamylase enzymes from Aspergillus to be between pH 3.5 and 4.15 (Amirul et al 1996;Sauer et al 2001).…”

Section: Experiments 1: Effect Of Phmentioning

confidence: 99%

Effect of pH on Fouling Characteristics and Deposit Compositions in Dry‐Grind Thin Stillage

et al. 2006

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Cereal Chem. 83(3):311-314Dry-grind corn processing facilities produce ethanol, carbon dioxide, and distillers dried grains with solubles (DDGS). To produce DDGS, drygrind corn processors concentrate thin stillage in multieffect evaporators. Concentration of thin stillage uses large amounts of energy, and efficient operation is important for long-term economic stability of the industry. Little data are available on fouling of evaporators during thin stillage concentration. We evaluated how thin stillage pH and acid type used during pH adjustment affected fouling as measured by induction period, fouling rate, and deposit composition. Using an annular fouling appa-ratus, fouling tests were conducted at pH 3.5, 4.0, and 4.5. In a second experiment, we used two types of acid, HCl or H 2 SO 4 , to adjust thin stillage to pH 3.5. Induction periods were shorter at pH 3.5 than at pH 4.0 or 4.5. As pH increased, fouling deposit protein decreased and ash increased. Concentrations of most elements, including P, Ca, Mg, Mn, and K, increased with an increase in pH. Phosphorus was the most abundant mineral element in fouling deposits. Induction periods were similar for the two acids. Thin stillage pH has an influence on deposit concentration, fouling rate, and induction period.

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“…Th' is was better than that of the amylase from B . amyloliguefaciens which loses about 50% of its activity when maintained at 70°C for 85 min (Kochhar and Dua 1990). T h e thermal stability of the amylase from Bacillus sp.…”

Section: Heat Ph and Salt Stability Of Amylase From Bacmusmentioning

confidence: 99%

Amylase production by a Gram‐positive bacterium isolated from fermenting tef (Eragrostis tef)

Lealem

Gashe

1994

Journal of Applied Bacteriology

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Bacillus sp. A‐001, which produced large amounts of amylase, was isolated from fermenting tef (Eragrostis tef) on tryptone soya agar supplemented with 1% starch. The organism grew between pH 4.5 and 10.5 with an optimum at 7–7.5. Growth occurred between 20 and 55°C but the optimum was about 35–40°C. At optimum medium pH (7.5) and a temperature of 35°C the organism entered the stationary phase after about 72 h and amylase production was at its highest (9.6 units ml‐1) at this time. Enzyme activity was optimal at pH 5.5 and 40°C and showed good thermal stability; it required 110 min to lose 50% of its activity at 70°C. The enzyme hydrolysed native starch (flour from tef, corn and kocho) to various oligosaccharides, including maltotriose, maltose and glucose.

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Thermostable liquefying ?-amylase fromBacillus amyloliquefaciens

Cited by 12 publications

References 13 publications

A highly thermostable amylase from a newly isolated thermophilicBacillussp. WN11

A highly thermostable amylase from a newly isolated thermophilicBacillussp. WN11

Effect of pH on Fouling Characteristics and Deposit Compositions in Dry‐Grind Thin Stillage

Amylase production by a Gram‐positive bacterium isolated from fermenting tef (Eragrostis tef)

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