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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.
*Corresponding author. E-mail:
nor_aini@upm.edu.my. Fax: +603 89467510.
Abbreviations: LAB, Lactic
acid bacterium; GRAS, generally recognized as safe;
DNS, dinitrosalicylic acid; HPLC, high
performance liquid chromatography; PCR, polymerase
chain reaction.
Accepted 28 May, 2010 |
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Lactococcus lactis
is a
Gram-positive bacterium widely used in the
production of
buttermilk 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. |
