Bacterial strain improvement for biomolecules through chemical and physical mutagens
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Date
2021-03-30
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Palampur
Abstract
Microorganisms are crucial life form present on earth, inhabiting all climatic zones including
high altitude Himalayan niches. Microbes can thrive in harsh environmental conditions due to
their ability to produce biomolecules such as enzymes and metabolites that perform
specialised biological functions. Biomolecules produced by microbes are in minute quantities.
Therefore, there is a need to increase the production for large scale applications through strain
improvement. Hence, the current study was focussed on the strain improvement of unique
bacterium Iodobacter sp. PCH194 through the application of chemical mutagens MMS, EMS,
and NMU and physical mutagen in the form of UV radiation. The isolate PCH194 coproduces PHA and violacein, which has wide industrial applications. Through systematic
applications of mutagens on wild-type PCH194, mutants with desired features were obtained
and designated as IN1, IN2, IN3, IN4, and IN5. Their growth kinetics at alleviated
temperature were observed. It was found that their growth temperature increased from 20 to
25C, and slow growth was also observed at 28C. However, the application of thermo
protectants glycine betaine and glutamate could not significantly enhance the growth at 28C.
There was a marked increase in growth, PHA and violacein production of the mutants at
20C. The PHA production was 1.24 mg/ml for IN5 and violacein production was 1.63 mg/ml
for IN2, whereas wild strain produced 0.42 mg/ml PHA and 0.20 mg/ml violacein,
respectively. In conclusion, the present study successfully increased the growth temperature
of Iodobacter sp. PCH194 from 20C to 25C and also enhanced the production of PHA and
violacein. Hence, generated mutants can further be used for process optimisation and scale-up
studies