24
D. Dasgupta Mandal et al.
3 Results and Discussion
3.1 Pigment Production in Batch Studies
The growth profile of bacterial isolate from Fig. 1a reveals that the bacterial isolate
has preferred fatty acid-containing powders and oils as carbon source in comparison
to nutrient broth and peptone glycerol media for growth and pigment production.
Nutrient broth and peptone glycerol broth yielded only 0.047 ± 0.001 g/L and 0.02
± 0.003 g/L productivity, respectively, after 60 h of incubation. It is important to note
that compared with this study, much higher productivity of prodigiosin in nutrient
broth (0.35 g/L) and peptone glycerol media (0.56 g/L) in similar process conditions
have been reported by Giri et al. (2004), using other strains of Serratia. The variations
in production may be due to the preferential nutritional choice of the selected strain
as certain carbon source may be responsible for catabolite repression (Kalivoda
et al. 2010). In the presence of fatty acid source-containing media, the bacterial
growth and prodigiosin production were considerable. There was time-dependent
enhancement in production in correlation with growth with maximum yield observed
at 60 h for peanut oil and palm oil and 72 h for peanut powder, beyond that there
was no significant yield enhancement. The highest productivity was observed in
case of peanut oil (5.36 ± 0.81 g/L) followed by palm oil (4.43 ± 0.72 g/L) and
peanut powder media (3 ± 0.45 g/L). Similar findings were reported by Giri et al.
(2004) where fatty acid as carbon source showed improved prodigiosin production
compared with conventional media. Further, this can be supported by the finding of
Aruldass et al. (2014) for prodigiosin production by S. marcescens UTM1 where
complex media were deemed to be poorly nutritious compared with chemically
defined simple media such as brown sugar. Palm oil as an alternate source of fatty
acids showed promising results in comparison with peanut oil that gave only 1.2-fold
higher production. However, peanut oil is the costliest edible oil in India (Economic
Times 2015), so, on economic point of view, palm oil as nutrient can be thought as
Fig. 1 a Growth of bacterial isolate in different fatty acid media and b pigment production
D. Dasgupta Mandal et al.
3 Results and Discussion
3.1 Pigment Production in Batch Studies
The growth profile of bacterial isolate from Fig. 1a reveals that the bacterial isolate
has preferred fatty acid-containing powders and oils as carbon source in comparison
to nutrient broth and peptone glycerol media for growth and pigment production.
Nutrient broth and peptone glycerol broth yielded only 0.047 ± 0.001 g/L and 0.02
± 0.003 g/L productivity, respectively, after 60 h of incubation. It is important to note
that compared with this study, much higher productivity of prodigiosin in nutrient
broth (0.35 g/L) and peptone glycerol media (0.56 g/L) in similar process conditions
have been reported by Giri et al. (2004), using other strains of Serratia. The variations
in production may be due to the preferential nutritional choice of the selected strain
as certain carbon source may be responsible for catabolite repression (Kalivoda
et al. 2010). In the presence of fatty acid source-containing media, the bacterial
growth and prodigiosin production were considerable. There was time-dependent
enhancement in production in correlation with growth with maximum yield observed
at 60 h for peanut oil and palm oil and 72 h for peanut powder, beyond that there
was no significant yield enhancement. The highest productivity was observed in
case of peanut oil (5.36 ± 0.81 g/L) followed by palm oil (4.43 ± 0.72 g/L) and
peanut powder media (3 ± 0.45 g/L). Similar findings were reported by Giri et al.
(2004) where fatty acid as carbon source showed improved prodigiosin production
compared with conventional media. Further, this can be supported by the finding of
Aruldass et al. (2014) for prodigiosin production by S. marcescens UTM1 where
complex media were deemed to be poorly nutritious compared with chemically
defined simple media such as brown sugar. Palm oil as an alternate source of fatty
acids showed promising results in comparison with peanut oil that gave only 1.2-fold
higher production. However, peanut oil is the costliest edible oil in India (Economic
Times 2015), so, on economic point of view, palm oil as nutrient can be thought as
Fig. 1 a Growth of bacterial isolate in different fatty acid media and b pigment production