Optimization of Alpha-Amylase Production in a Batch Fermenter Using Bacillus licheniformis PTCC 1721

Articles in Press

Document Type : Research Paper

Authors
Mahsa Chaharmahali 1
Seyed Safa-ali Fatemi 2
Fatemeh karbalaee safar lavasani 3
Neda Mousavi-Niri 4
Saeed Aminzadeh 5
1 Department of Systems Biotechnology, National Institute for Genetic Engineering and Biotechnology, Tehran, Iran
2 Department of Systems Biotechnology, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB)
3 NIGEB
4 Department of Biotechnology, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Islamic Azad University
5 Department of Systems Biotechnology, National Institute for Genetic Engineering and Biotechnology, Tehran, I.R. of Iran
10.22034/cmr.2026.8626.3324
Abstract
In this study, we optimized alpha-amylase production by the thermophilic bacterium Bacillus licheniformis PTCC1721 using a batch fermentation system designed to enhance yield while minimizing production expenses. Precultures were grown in nutrient-rich media formulated from corn and soybean components, and fermentation was conducted in a 2-L fermenter under rigorously monitored operating conditions. To identify the key factors influencing enzyme production, the effects of starch concentration, pH, temperature, interactions between temperature and pH, interactions between temperature and starch, agitation speed and aeration rate were systematically examined using a Taguchi L8 design followed by Analysis Of Variance (ANOVA). Optimization revealed that a temperature of 45°C, pH 8, an agitation speed of 300 rpm, a starch concentration of 20g/L, and an aeration rate of 1vvm over 30 hours resulted in maximal enzyme production. Under these optimal conditions, alpha-amylase activity increased from 60 U/l to 428 U/l, representing a 1/7 fold improvement compared to preoptimization levels, while the specific activity reached 440 U/mg. The combined use of a low-cost corn–soy-based culture medium and optimized process parameters establishes an efficient and economically viable approach for alpha-amylase production. These findings provide a strong foundation for further development and industrial scale-up of the production process.

Keywords

Subjects

Cellular and Molecular Research (Iranian Journal of Biology)

Articles in Press, Accepted Manuscript
Available Online from 09 May 2026

  • Receive Date 16 May 2025
  • Revise Date 02 December 2025
  • Accept Date 25 April 2026