Abstract
Aim:
To
produce the highest amount of cold-active alpha-amylase within a short time
using mesophilic bacteria with optimized media to save the energy consumption
cost and obtain higher enzyme production.
Methodology:
Amylase
producing twenty-three strains were isolated on starch peptone agar plates.
Among them, one strain, A5 was selected on the basis of highest clear (12 mm)
zone on starch peptone agar plates. It was characterized and identified
following Bergey's Manual of Systematic Bacteriology. Enzyme was
characterized as Cold alpha amylase. All physico-chemical parameters
(temperature, pH, Inoculum size) including carbon, nitrogen, metal ion and
amino acid sources were optimized for maximum production of the enzyme. The
optimized media was used for enhancing the cold active amylase production.
Results:
The
strain, A5 was identified as Bacillus cereus RGUJS2023 by 16S rRNA sequencing
analysis for further experiments. This strain showed the highest activity
(9.922± 0.143 U ml-1) on the basal starch peptone media. Though,
crude enzyme showed its activity at 4°C to 48°C
temperature, but the temperature was 28°C. The highest cold active enzyme was
produced (18.87±0.06 U ml-1) at 16 hr of bacterial growth at 35 °C
with a pH 6.5 in the optimized media containing 0.5% starch, 0.1% peptone and
0.03% MgSO4.7H2O as a carbon, nitrogen and metal ion
sources, respectively, with addition of 0.03% arginine.
Interpretation:
The
cold active alpha amylase could be used commercially for the benefit of
pharmaceutical and starch processing industries.
Key
words: Bacillus
cereus
RGUJS2023, Cold-active amylase, Starch hydrolysis
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