African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5232

Full Length Research Paper

Production of alkaline protease by Bacillus subtilis using solid state fermentation

Saba Imtiaz, Hamid Mukhtar* and Ikram-ul-Haq
Institute of Industrial Biotechnology, GC University, Lahore-54000, Pakistan.
Email: [email protected]

  •  Accepted: 25 February 2013
  •  Published: 16 April 2013


 The present study describes the optimization of nutritional and cultural parameters for the production of alkaline protease by Bacillus subtilis under solid state conditions. Among cultural conditions, incubation temperature, incubation period and moisture level of the substrate were optimized and it was found that maximum production of alkaline protease was observed at 37°C and moisture to substrate ratio of 1:1 after 48 h of incubation period. Among different nutritional parameters, the effects of different diluents, carbon and nitrogen sources on the enzyme production were studied. Maximum enzyme production (101.23 U/g) was observed when D2 {(% w/v) CaCO3, 0.05; peptone, 0.1; glucose, 0.1 and yeast extract, 0.1} was used to moisten the substrate. The best carbon source for the production of alkaline protease by B. subtilis was found to be sucrose at a concentration of 1%. Similarly, nutrient broth (1.5%) and diammonium hydrogen phosphate (0.1%) were found to be best organic and inorganic nitrogen sources, respectively. It was also found that the maximum protease (126.8 U/g) was produced when 25% (v/w) inoculum was used to inoculate the fermentation flasks.


Key words: Fermentation, carbon, nitrogen, inoculum, incubation temperature.