Roberto DePhilippis

20 Pages·2016·2.21 MB·English

Roberto De Philippis
DepartmentofAgrifoodProduction and EnvironmentalSciences(DISPAA),
UniversityofFlorence; FLORENCE -Italy
•
capability of the microbial biomass to remove
metal ions at low levels of concentration
•
possibility to treat waters containing multiple
metals
•
fast kinetics of metal removal
•
possible utilization of naturally abundant
renewable biomaterials
•
metal recovery
•
metal selectivity
Can EPS-producing cyanobacteria be
considered efficient metal biosorbents?
Sheath (thin layer surrounding cells or cell groups)
Chroococcus sp. Phormidiumsp.
Capsule (thick and slimy layer, associated
with cell surface)
Cyanothecesp Cyanospira capsulata
Slime (mucilaginous material dispersed
around the organism)
Cyanothece PCC8801 NostocPCC7936
RPS (water-soluble polysaccharide, released
into the culture medium)
Cyanospira capsulata
De Philippis & Vincenzini FEMS MicrobiolRev 1998
3 days old colture 20 days old colture
Pereira et al. FEMS MicrobiolRev 2009
40
35
s
%
n 87
i
a30
r
t
25
s
f
20
o
e
15
g
a
t10
n
e
5
c
r
e
0
P
0% 0.1-5 % 5.1-20% 20.1-50% > 50.1% present
Uronic acid content (% on EPS DW)
Molecular basis of metal biosorption by
EPS-producing CB [Me cations]
Me n+
Me n+
Me n+
Me n+
Me n+
Me n+
Me n+
De Philippis, Colica, Micheletti ApplMicrobiolBiotechnol 2011
Molecular basis of metal biosorption by
EPS-producing CB [Me cations]
82,9
80
amide
75 groups FT-IR Spectra
70 carboxylic
groups
65
sulfate
60 groups
55
%T
50
45
- Cu
40
35 + Cu
30
26,7
4000,0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 450,0
cm-1
Micheletti, Pereira, Mannelli, Moradas-Ferreira, Tamagnini, De Philippis
ApplEnviron Microbiol, 2008
Field experiments
at pH 2
at pH 4.2
Molecular basis of metal biosorption by
EPS-producing CB [Me oxyanions]
HCrO -/ CrO 2-
4 4
Cr O 2-
2 7
Possible interactions between EPS-
CB biomass and HCrO -/Cr O 2-
4 2 7
Cr3+
Cr3+
Cr3+ Cr3+
HCrO -
4
Acid
Cr3+ (at pH 2)
pretreatment
Cr3+
Cr3+
Cr3+
Cr3+ Cr3+
Colica, Mecarozzi, De Philippis ApplMicrobiolBiotechnol2010