A highly thermostable amylase from a newly isolated thermophilic<i>Bacillus</i>sp. WN11

Mamo, Gashaw; Gashe, Berhanu A.; Gessesse, Amare

doi:10.1046/j.1365-2672.1999.00685.x

Cited by 45 publications

(25 citation statements)

References 28 publications

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“…The addition of 2 − 5% soluble starch delayed the decrease in the activity of Thermomonospora fusca α-amylase incubated at 70℃ (Busch and Stutzenberger, 1997) and delayed the decrease in the activity of thermophilic Bacillus sp. WN11 incubated at 105℃ (Mamo et al, 1999). These studies concluded that starch had a stabilizing effect on amylase, although they did not measure k 0 and E a values.…”

Section: Results and Discussion α-Amylase Activity At High Temperaturesmentioning

confidence: 97%

Effect of Starch on the Inactivation of Amylase in Starch-Containing Foods

Koyama

Shono

Taguchi

et al. 2013

FSTR

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The quality of starch-containing foods is significantly impaired by contamination with small amounts of α-amylase, which hydrolyzes the starch and causes viscosity loss. We examined the effect of different temperatures and times on inactivation of α-amylase in starch-containing foods. Model foods containing a known amount of human salivary α-amylase (HSA) were incubated at temperatures from 60 to 80℃ for 30 min. In the case of a 3% starch suspension incubated at 70℃, it took 10 min before the viscosity loss ceased, by which time the viscosity was halved. In 0.1 − 3% starch suspensions at pH 5.5, the inactivation of HSA could be described by a first order kinetic model. The presence of starch decreased the inactivation rate constant by decreasing the Arrhenius frequency factor. To prevent viscosity loss by α-amylase contamination in starch-containing foods, the inactivation time and temperature should be increased with increasing concentration of starch.Keywords: α-amylase, inactivation, thermostability, starch-containing food, viscosity *To whom correspondence should be addressed. E-mail: k-koyama@housefoods.co.jp IntroductionEffective use of starch in the food industry requires a thorough understanding of the enzymatic properties of amylase and the degradation behavior of starch. The increase in viscosity of starch-containing foods is largely due to the gelatinization of starch during heating. Viscosity is an important quality factor for thickened foods, such as soups, stews and curries that contain 5% or less starch. If a trace amount of amylase contaminates starch-containing foods, it can hydrolyze the starch and cause viscosity loss. Possible sources of amylase contamination include honey, spices, grains, fermented food, human saliva left on a tasting spoon and enzyme-containing dishwashing detergent.To prevent viscosity loss by non-thermophilic amylase contamination, starch-containing foods need to be heated to inactivate the amylase. However, using more heat than is necessary will reduce the freshness of the food. Food manufacturers have empirically found that heating at approx. 80℃ results in amylase inactivation.The thermostability of amylase increases in the pres-

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Section: Results and Discussion α-Amylase Activity At High Temperaturesmentioning

confidence: 97%

Effect of Starch on the Inactivation of Amylase in Starch-Containing Foods

Koyama

Shono

Taguchi

et al. 2013

FSTR

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“…There are several studies demonstrating the effects of metal ions on bacterial and fungal α-amylases. Although, any specific ion is not required for the catalytic activity of amylase but there are several reports on the Ca 2+ dependent α-amylase from Bacillus spp [25,[40][41][42][43]. It has been reported that α-amylase is a metalloenzyme containing at least one activating Ca 2+ ion.…”

Section: Effect Of Metal Ions On α-Amylase Activitymentioning

confidence: 99%

Production, Partial Purification and Characterization of α-Amylase from High Molecular Weight Polycyclic Aromatic Hydrocarbons (HMW-PAHs) Degrading Bacillus subtilis BMT4i (MTCC 9447)

Lily¹,

Bahuguna²,

Bhatt³

et al. 2012

Turk J Bioch

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“…WN11, a thermophile earlier isolated in our laboratory (Mamo et al 1999). The basal medium used was composed of (g/l): NaCl, 1; KH2PO4, 2; CaCl2, 0·1; MgSO4, 0·1; and trace mineral solution, 20 ml.…”

Section: The Organism and Cultivation Conditionsmentioning

confidence: 99%

“…Amylase activity was assayed based on the amount of reducing sugar released following the dinitrosalicylic acid (DNS) method as described previously (Mamo and Gessesse 1997). One unit of amylase activity was defined as the amount of enzyme that released 1 mmol of reducing sugar equivalent to glucose per min under the assay condition.…”

Section: Enzyme Assaymentioning

confidence: 99%

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Effect of cultivation conditions on growth and α‐amylase production by a thermophilicBacillussp.

Mamo

Gessesse

1999

Letters in Applied Microbiology

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Growth and amylase production by Bacillus sp. WN11 was studied under different cultivation conditions. Maximum growth was observed at 65 °C while the highest amylase production was recorded at 55 °C. Good amylase production and growth was observed at an initial medium pH of 5 and 6. No detectable growth was observed at pH 4 and 9. The organism grew better and produced higher levels of amylase activity using proteose peptone and tryptone as nitrogen sources. No growth was observed when NO3+, NH4+ and urea were used as nitrogen sources. Among defined carbohydrates, tested starch and maltose supported good growth and amylase production, with the highest productivity recorded in the presence of starch (24 U/ml). Compared to starch, barley and corn flour resulted in maximum amylase production.

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A highly thermostable amylase from a newly isolated thermophilicBacillussp. WN11

Cited by 45 publications

References 28 publications

Effect of Starch on the Inactivation of Amylase in Starch-Containing Foods

Effect of Starch on the Inactivation of Amylase in Starch-Containing Foods

Production, Partial Purification and Characterization of α-Amylase from High Molecular Weight Polycyclic Aromatic Hydrocarbons (HMW-PAHs) Degrading Bacillus subtilis BMT4i (MTCC 9447)

Effect of cultivation conditions on growth and α‐amylase production by a thermophilicBacillussp.

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