| dc.description.abstract | This research investigated the feasibility of Iron oxide nanoparticles (IONPs)
synthesis using Physarum polycephalum, a fast growth, high biomass production
without cell walls slime mold species, in the presence of excess ferric and ferrous
salts. The effects of the high salt concentrations on the biomass and bioactivities
of the exopolysaccharides (EPSs) of this species were also analyzed. In addition,
this species has reportedly produced a high amount of EPSs, which process some
significant biological activities and iron ions could suggestively influence both the
growth and EPSs production.
IONPs were successfully detected from the microplasmodia (biomass) of P.
polycephalum in the cultures containing excess iron salts including 40 mM
FeCl3·FeCl2 and 40 mM FeCl2, with the average particle size was 16 ± 6 nm and
24 ± 2 nm, respectively. There were no IONPs observed in the standard culture (3
mM FeCl2).
The biomass yield of the standard culture, 40 mM FeCl3·FeCl2 culture, and 40 mM
FeCl2 was 6.08 ± 0.15 g/L, 4.99 ± 0.26 g/L, and 5.34 ± 0.17 g/L, respectively. The
crude EPS production of these cultures was 3.55 ± 0.09 g/L, 1.82 ± 0.09 g/L, and
2.54 ± 0.10 g/L, respectively. All the EPSs showed no antibacterial inhibition
against Staphylococcus aureus at the tested concentration (20 mg/mL). However,
the presence of excess concentrations of ferric salts seemed to negatively influence
the antioxidant activities of the EPSs. Specifically, the antioxidant properties of
the EPSs in the 40 mM FeCl3·FeCl2 and FeCl2 medium had no antioxidant
activities, whereas the antioxidant activity of those in the standard medium
displayed remarkable antioxidant activity at the half inhibitory concentration
(IC50) of 2.93 mg/mL, which was compared with that of the ascorbic acid (0.63
mg/mL). | en_US |
