Organic solvent tolerance of an α-amylase from haloalkaliphilic bacteria as a function of pH, temperature, and salt concentrations.
A haloalkaliphilic bacterium was isolated from salt-enriched soil of Mithapur, Gujarat (India) and identified as Bacillus agaradhaerens Mi-10-6₂ based on 16S rRNA sequence analysis (NCBI gene bank accession, GQ121032). The bacterium was studied for its α-amylase characteristic in the presence of organic solvents. The enzyme was quite active and it retained considerable activity in 30% (v/v) organic solvents, dodecane, decane, heptane, n-hexane, methanol, and propanol. At lower concentrations of solvents, the catalysis was quite comparable to control. Enzyme catalysis at wide range of alkanes and alcohol was an interesting finding of the study. Mi-10-6₂ amylase retained activity over a broader alkaline pH range, with the optimal pH at 10-11. Two molars of salt was optimum for catalysis in the presence of most of the tested solvents, though the enzyme retained significant activity even at 4 M salt. With dodecane, the optimum temperature shifted from 50 °C to 60 °C, while the enzyme was active up to 80 °C. Over all, the present study focused on the effect of organic solvents on an extracellular α-amylase from haloalkaliphilic bacteria under varying conditions of pH, temperature, and salt.
Department of Biosciences, Saurashtra University, Rajkot 360005 Gujarat, India.
Sandeep
S
Pandey
S P
SP
Singh
D000438:Alcohols / Q000737:chemistry; D000473:Alkanes / Q000737:chemistry; D000645:Ammonium Sulfate / Q000737:chemistry; D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000302:isolation & purification* / Q000378:metabolism; D004795:Enzyme Stability; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007194:India; D007700:Kinetics; D012336:RNA, Ribosomal, 16S / Q000032:analysis*; D055049:Salt Tolerance; D012965:Sodium Chloride / Q000737:chemistry; D012988:Soil Microbiology; D012997:Solvents / Q000737:chemistry*; D000516:alpha-Amylases / Q000302:isolation & purification* / Q000378:metabolism
D000438:Alcohols; D000473:Alkanes; D001426:Bacterial Proteins; D012336:RNA, Ribosomal, 16S; D012997:Solvents; D012965:Sodium Chloride; D000516:alpha-Amylases; D000645:Ammonium Sulfate