LBE’s research activities
Christof Holliger
September 2018
ENAC – ISTE
Laboratory for
Environmental Biotechnology
Two main research topics
Aerobic granular sludge (AGS) for
wastewater treatment
Organohalide respiration of
chlorinated solvents
Granules are compact biofilm
structures
after 1 min of settling
• more compact systems
• higher flexibility
• better settling characteristics
easier separation of
sludge and water
“Future of wastewater
treatment”Source: Water21, April 2013
• C, N and P removal within
one reactor
Advantages of AGS
Process
parameters
Micro-
environmental
conditions
C-P-N
nutrient removal
from wastewater
granule bacterial community
Multivariate statistical methods
Multilevel correlations
Nitrifiers
Denitrifiers
Polyphosphate-
accumulating
organisms (PAO)
Glycogen-accumulating
organisms (GAO)
Understanding aerobic granular sludge
systems at the community level
(enhanced) natural attenuation of
chloroethenes contamination
The anaerobic respiration
hypothesis
0 0,5 (volts)-0,5
ReductionCT to CF
O2 to H2O
PCE to TCE
NO3 to NO2
DCB to MCB
DCE to VC
SO4 to H2S
CO2 to CH4
Ferredoxin red. to ox
NADH to NAD
Oxidation
Free energy (kJ/mol of electrons transferred
0 +50-50
0 0,5 (volts)-0,5
ReductionCT to CF
O2 to H2O
PCE to TCE
NO3 to NO2
DCB to MCB
DCE to VC
SO4 to H2S
CO2 to CH4
Ferredoxin red. to ox
NADH to NAD
Oxidation
Free energy (kJ/mol of electrons transferred
0 +50-50
Tentative model of the tetrachloroethene
respiration chain of Dehalobacter restrictus
HynC2
Fe
Fe
cyt b
Hyn
S2
Hyn
L2
Ni
Fe
Fe-S
Fe-S
Fe-S
Pce
A
Co
Fe-S Fe-S
PceB« PceC »
Fe
FAD
H2 2H+
½PCE ½DCE + Cl-
2H+
2H+
H+
2e-
MKH2
MK
2e-
??
H+/e- = 1.5(measured for Dehalobacter: 1.25±0.2)
HynC2
Fe
Fe
cyt b
Hyn
S2
Hyn
L2
Ni
Fe
Fe-S
Fe-S
Fe-S
Pce
A
Co
Fe-S Fe-S
PceB« PceC »
Fe
FAD
2H +
½PCE ½DCE + Cl-
2H+
2H+
H +
2e-
MKH2
MK
2e-
? ?
H+/e- = 1.5(measured for Dehalobacter: 1.25±0.2)
approx. 600 members
6 sections:
clinical microbiology
prokaryotic biology
environmental microbiology
mycology
virology
lay communication
events organized:
2-days Annual Meeting
1-day Satellite Symposia or
specific section events, e.g.
Swiss Microbial Ecology,
Swiss Virology Meeting
Committee:
President (3-years term)
Past president (1y) or
President elect (2y)
Treasurer
Section leaders (6)
(General secretary)
Major problem:
Financial situation:
► membership fee
payment
► income < expenses