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Keywords:

  • L-asparaginase;
  • kinetic modeling;
  • Bacillus aryabhattai ITBHU02;
  • thermodynamic properties;
  • enzyme formation–inactivation kinetics

Abstract

BACKGROUND

An unstructured model for batch culture production of L-asparaginase by Bacillus aryabhattai ITBHU02, by means of the Luedeking–Piret incorporated logistic equation, was developed explaining the correlation between growth dynamics and enzyme production kinetics with respect to glucose depletion at different levels. The main goal was to build up a means for process optimization, design, control and analysis of L-asparaginase production. Various thermodynamic parameters were estimated to comprehend enzyme stability and affiliated industrial applicability.

RESULTS

Specific growth rate maxima were increased with increasing initial glucose concentration, whereas the specific productivity was best supported at a glucose concentration 5.0 g L-1. The fermentative production of L-asparaginase was greatly influenced by oxygen supply, reaching a maximum level at an aeration rate of 0.6 vvm. The activation energies for growth and death rate were 33.8±6.0 and 99.8±9.0 kJ mol-1, respectively, with activation enthalpy values of enzyme formation and thermal deactivation 70.2±9.0 and 46.1±11.0 kJ mol-1, respectively.

CONCLUSION

The economic production of L-asparaginase by B. aryabhattai was achieved efficiently at low glucose concentration and mild aeration. Endogenous metabolism of the strain for L-asparaginase synthesis was thermostable up to 40°C, which makes the strain commercially important as it can be utilized for cost-effective L-asparaginase production within countries such as India, where 35–40°C temperatures are quite common. © 2013 Society of Chemical Industry