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Rheology of liquid media influences bacterial physiology Rheology of liquid media influences bacterial physiology

Rheology of liquid media influences bacterial physiology - PowerPoint Presentation

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Rheology of liquid media influences bacterial physiology - PPT Presentation

Maja Borić Tjaša Danevčič David Stopar University of Ljubljana Biotechnical Faculty Importance of rheology in biotechnological processes Rheology studies the flow of liquids or soft matter ID: 634826

viscosity rheology growth physiology rheology viscosity physiology growth flow activity bacterial harveyi rate water subtilis respiration coli phosphofructokinase cycle

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Slide1

Rheology of liquid media influences bacterial physiology

Maja

Borić

,

Tjaša

Danevčič

, David

Stopar

University of Ljubljana, Biotechnical FacultySlide2

Importance of rheology in biotechnological processes

Rheology

studies the flow of liquids or soft matter

Water treatment plants, bioreactors

Influences pumping, hydrodynamics, mass transfer rates and sludge-water separation

Changes molecular diffusion as well as movement of microorganisms

Can a change in liquid medium rheology cause a change in bacterial physiology?Slide3

Changing medium rheology in the lab

Ideal polymer:

increases viscosity

changes Newtonian liquid to non-Newtonian

can not be degraded by bacteria and used as a nutrient

does not affect other

physico

-chemical factors (pH, water activity, DOC)

Hydroxyethyl

cellulose (HEC)

Viscosity range: 0.8

mPas

– 26.5

mPas

Model organisms:

Bacillus

subtilis

Escherichia coli

Vibrio

harveyiSlide4

Physiology of

Bacillus

subtilis

Growth rate increases but then returns to the previous level

PFK (phosphofructokinase) –

glycolysis

GPD (glucose-6-P-dehydrogenase)

pentose phosphate pathwayPK (piruvate kinase) – flow to the citric acid cycle

Respiration activity is the same at all viscositiesSlide5

Physiology of

E

s

cherichia

coli

At the highest tested viscosity the growth rate and respiration activity decreased significantly

PFK (phosphofructokinase) –

glycolysis

GPD (glucose-6-P-dehydrogenase)

pentose phosphate pathway

PK (

piruvate

kinase)

flow to the citric acid

cycleSlide6

Physiology of

Vibrio

harveyi

V.

harveyi

increased its respiration activity in order to maintain an unchanged growth rate. Despite this, the growth rate decreased at the highest tested viscosity.

PFK (phosphofructokinase) –

glycolysis

GPD (glucose-6-P-dehydrogenase)

pentose phosphate pathway

PK (

piruvate

kinase)

flow to the citric acid cycleSlide7

Growth efficiency

V

.

harveyi

(A

)

E

. coli

(B) B. subtilis (C) Slide8

Main conclusions and outlooks

Noteworthy differences in bacterial physiology at increased viscosity

/

changed rheology:

variability in bacterial response

Changes in viscosity / rheology can affect

:

growth rates

total metabolic activityefficiencycarbon flow through central metabolic pathwaysOther bacteria might also be subject to changes in environmental viscosity/rheology – can this be the case in water treatment plants and other biotechnological settings?Slide9

Acknowledgements

co-workers

at the Chair of Microbiology, Biotechnical Faculty, Ljubljana

prof. dr. David

Stopar

dr.

Tjaša

DanevčičJUB, d.d.Slovenian Research Agency