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Insight on biochemical characteristics of thermotolerant amylase isolated from extremophile bacteria Bacillus vallismortis TD6 (HQ992818)

Suganthi, Chandrasekaran, Mageswari, Anbazhagan, Karthikeyan, Sivashanmugam, Gothandam, Kodiveri Muthukaliannan
Microbiology 2015 v.84 no.2 pp. 210-218
Bacillus vallismortis, alanine, bacteria, calcium, calcium chloride, carbon, detergents, enzyme activation, extremophiles, heat tolerance, inoculum, iron, laundry, magnesium, mercury, metal ions, nitrogen, pH, salt tolerance, sediments, sodium chloride, sodium nitrate, starch, temperature, washing, India
Halotolerant bacterium Bacillus vallismortis (HQ992818) was isolated from saltern sediments in India, and produced significantly high levels extracellular amylase. A detailed investigation on the culture conditions including period of incubation, media pH, and inoculum size in addition to different sources of carbon and nitrogen, metal ions, NaCl, and amino acids was carried out for optimized production. Maximum amylase production (62 U/mL) was attained after 26 h of incubation. The optimized conditions for maximal production of amylase were found to be 1% NaCl, pH 8, temp 37°C, 1% starch, 1% sodium nitrate, phenyl alanine (0.01%) and calcium chloride (10 mM). The biochemical characteristics of the extracellular amylase were studied with respect to change in temperature, pH and metal ions. The enzyme was found to be optimally active in the temperature range of 40–70°C and pH 8. Activation of the enzyme by Ca²⁺(135%), Fe²⁺(113%) and Mg²⁺(109%) occurred at 5 mM concentration and strongly inhibited by Hg²⁺, Zn²⁺and Mn²⁺occurred at 10 mM. Significant compatibility of the enzyme with the commercial laundry detergents and the results of washing performance test confirmed its effectiveness. Available data on the optimized culture conditions enables for easily adaptable setup of large scale production of the enzyme for use in detergent formulations.