African Journal of

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12254

Full Length Research Paper

Effects of agitation speed, temperature, carbon and nitrogen sources on the growth of recombinant Lactococcus lactis NZ9000 carrying domain 1 of aerolysin gene

Siti Balkhis Ibrahim1, Nor’Aini Abdul Rahman1*, Rosfarizan Mohamad1 and Raha Abdul Rahim2
1Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia. 2Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
Email: [email protected]

  •  Accepted: 28 May 2010
  •  Published: 31 August 2010


Lactococcus lactis is a Gram-positive bacterium widely used in the production ofbuttermilk and cheese. Recently, the bacterium becomes famous as the genetically modified organism can be used alive for the treatment of disease. In this study,different cultural conditions based on agitation speed and temperature on the growth of recombinant L. lactis NZ9000 harboring domain 1 of aerolysin gene (NHD1Aer) were investigated using shake flask experiment. The effect of different carbon (glucose, sucrose and lactose) and nitrogen (yeast extract, peptone, NH4Cl, (NH4)2SO4, and urea) sources in M17 medium on the cell accumulation were also tested. The results showed that the highest cell concentration (3.22 g/L, µm = 0.58 h-1) was obtained when the cultivation was incubated at 27°C and at agitation of 100 rpm. The cells growth was markedly improved when utilizing glucose and peptone/yeast extract as carbon and nitrogen sources, respectively. The aerolysin gene in the cells after four generation time was extracted and then analyzed using agarose gel electrophoresis. The results obtained showed a 250 bp band amplified of domain 1 of the aerolysin gene.


Key words: Aerolysin, Lactococcus lactis, fermentation, one-factor-at-a-time.


LAB, Lactic acid bacterium; GRAS, generally recognized as safe;DNS, dinitrosalicylic acid; HPLC, high performance liquid chromatography; PCR,polymerase chain reaction.