full issue - Association of Biotechnology and Pharmacy

Current Trends in Biotechnology and Pharmacy
Vol. 5 (3) 1282-1297 July 2011, ISSN 0973-8916 (Print), 2230-7303 (Online)
1290
is that glucose or other simple carbon sources
cause catabolite repression in which the
production of an enzyme of secondary metabolite
biosynthesis is inhibited.
The growth profile and antibacterial
biosynthesis by the tested organism was not only
affected by the nature of the used carbon source,
but also with its level. Results (Fig. 3B) showed
that the activity increased with increasing the
starch concentration till it reached a maximum
of 30 mm at 10 gm/l after which it remained
constant while the dry weight values kept
increasing with increasing starch concentrations.
Antibiotic production from alkaliphilic
actinomycetes isolate A2D, identified as S.
tanashiensis strain A2D, was higher in medium
having glucose (1 %) as carbon source while
highest biomass resulted on using 1.5 %(w/v)
glucose concentration (31). However, maximum
growth and antibiotic production by
Streptomyces sp. 201, were obtained in medium
supplemented with mannitol as a sole carbon
source followed by sucrose and glycerol (32).
Our results showed that organic nitrogen
sources such as peptone, corn steep liquor and
specially yeast extract were highly favorable for
anticandidal activity although this doesn’t
necessarily correlate to the growth of
Nocardioides luteus, as shown in Fig. 4A. On
the other hand, the tested inorganic nitrogen
sources resulted in a decreased anticandidal
production that also doesn’t correlate with
growth. Maximum inhibition zone was observed
on using yeast extract. Therefore, it was chosen
as a sole nitrogen source instead of casein and
KNO 3
in the proceeding work. The activity
increased with increasing the nitrogen source
concentration till it reached a maximum at the
concentration 3.76 gm/l, then constant through
the concentration 4 gm/l. Thereafter, it began to
decrease. The dry weight increased gradually as
well by increasing the yeast extract
concentrations until reaching 4 gm/l, after which
it started to decrease, Fig. 4B. The superiority of
the organic nitrogen sources has been reported
by many investigators (30-33).
Fig. 4. Role of nitrogen nutrition on the growth and anticandidal activity of N.luteus
A. Effect of nitrogen source B. Effect of nitrogen concentration
Studies on the production of actinomycin by Nocardioides luteus