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