Microorganisms from extreme habitats for use in biological

technologies to LRW treatment

The 8th International Symposium on Technetium and Rhenium: Science and Utilization

Safonov1, S. Gavrilov2, T. Khijniak2, K. German1, I. Troshkina3

1Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia 2Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia 3Mendeleev University of Chemical Technology Moscow, Russia

Why bacteria?

Small agents for Me reducing in environments in big quantities (102-103 cell per ml in water 103 - 107 per 1 cm3 in soils

Bacteria can survive and be efficient in extreme conditions: thermophilic 50-90 oC, alkaliphile pH 10-11, acidophile (pH 1-2), ionizing radiation dose up to 1-10 kGr

Good economic parameters in comparison with some chemical methods

“Green chemistry techniques”: no toxic reagents, acids, alkalines in high concentrations

Different abilities of cells biochemistry: oxidizing organic matter, reducing nitrate, sulphate, metals, sorption metals on cell wall, membrane and other organoids.

High speed of division rate of bacteria 1 time per 30 min in geometrical progression

Ability to live in anaerobic conditions, synthesizing Corg for cell growth from CO2 and H2O

Some mechanism of Me interaction

Tc (VII, IV) precipitation in insoluble sulfide

Strategy of work

Bacteria isolating on different cultural media

Studying of bacteriametabolic activity forMe insolubilization

Searching microorganismsin samples from extreme

conditions

Development of methods for bacteria using in situ and inapparatus

WANTED

Bacteria fromHigh salinity, high & low

pH conditions, high temperature for good job!

Bacteria from high salinity and alcaliphilic condition

Kulunda Steppe soda lake, in south-eastern Siberia (Altai, Russia), salinity up to 150 g/l, pH 10,5-11

0

20

40

60

80

100

0 10 20 30 40

% o

f tec

hne

tium

Time (hours)

Are able to: 1. reduce Tc (VII) to Tc (IV) in alkaline conditions (pH 10.5)2. reduce Re (VII) to Re (IV)3. reduce U (VI) to U (IV)4. Reduce NO3

- to N2

Tc (VII)

Tc (IV)

Dead cells

Thermal springs of Kuril Islands t>90°C salinity up to 70 g/l

Bacteria from high temperature condition

Are able to: 1. reduce Tc (VII) to Tc (IV) in neutral and acid conditions (pH 4.5-8)2. reduce U (VI) to U (IV)

uramphite; (NH4)(UO2)(PO4)·3H2O

ningyoite; (CaU(PO4)2·H2O)

Bacteria from repository of liquid medium RW

Deep (380-410 m) liquid repository of radioactive wastes Severniy, Russia Krasnoyarsk region. C NO3

- 1-300 g\l,

Are able to: 1. reduce Tc (VII) to Tc (IV) in neutral conditions (pH 7-8)2. reduce U (VI) to U (IV) 3. Reduce NO3

- to N2

4. Reduce SO42- to H2S

5. Sorb U on cell wall and in cytoplasm

Perspective ways of using

1. Development and design of flow-through bioreactor for the decontamination of  LLRW from uranyl cations,  pertechnetate anions

laboratory system based on immobilized cells of sulfate-reducing bacteria. Pertechnetate reduction with and without donor, respectively.

Designed laboratory system will be tested for simultaneous reduction of uranium and technetium at the “Radon”.

Technetium reduction by sulphate-reducing bacteria with different donors – H2 (▲), formate (∆), lactate (□).

Re precipitation from liquids

Perspective ways of using

Biological reduction of pertechnetate ion in the implementation of biobarrer technology

1. reducing Tc (VII) to Tc (IV)2. reducing U (VI) to U (IV) 3. Reducing NO3

- to N2

4. Reducing SO42- to H2S and precipitation Tc in sulfides form

5. Sorption U on cell wall and in cytoplasm6. Consumption O2 and Decreasing Eh to “-” zone

Thank you for your attention!