Isolation and Enrichment of soil bacteria

Regina Gohl, K. Noreen Boyle

02/11/2011

University of Oldenburg - ICBM - Practical course Physiology of bacteria (Group B1) – final presentation

Introduction

•1 soil probe 2 experiments

Regina Gohl, K. Noreen Boyle ICBM Uni Oldenburg 2

Introduction Aims & Expectations Course results Summary

Isolation

Enrichment

? Medium variation

Dilution series

37 °CPasteurisationNitrogenNitrogen + yeastSaltSalt+yeastAcidicAlkaline

Aims and expectations

•Cultivation of soil bacteria•Determination of abundance•Comparison: fast vs abundant•Influence of different media

Introduction Aims & Expectations Course results Summary

Expectations Direct isolation

Enrichment

Types of bacteria

several one - few

Colony size small large

Growth slow fast

Conclusion abundant fast growing

Regina Gohl, K. Noreen Boyle ICBM Uni Oldenburg 3

Direct Isolation

Introduction Aims & Expectations Course results Summary

Cells/g soil

3.1 x 10^6

5.4 x 10^6

3.3 x 10^6

1.9 x 10^6

4.7 x 10^6

1.9 x 10^6

1.0 x 10^6

0.8 x 10^6

2.8 x 10^6 cells/g soil

~1 % of bacteria can be cultured in the lab

~ 10^9 bacteria/g soil

Less bacteria than expected

Regina Gohl, K. Noreen Boyle ICBM Uni Oldenburg 4

Direct Isolation

Introduction Aims & Expectations Course results Summary

Regina Gohl, K. Noreen Boyle ICBM Uni Oldenburg 5

Enrichment

Introduction Aims & Expectations Course results Summary

Treatment Oxidase test

Gram test Catalase test

Increased temperature

+ - - - - -

Pasteurisation + - - - + +

- nitrogen source - + +

-nitrogen source + yeast extract

+ + +

+ salt + + +

+ salt + yeast extract

+ + +

acidic + + +

alkaline + + +http://www.laborwissen.de/wiki/tiki-index.php?page=Katalase-Test

Regina Gohl, K. Noreen Boyle ICBM Uni Oldenburg 6

Enrichment

Introduction Aims & Expectations Course results Summary

Treatment Motility Growth Size Shape

Increased temperature

mobile fast large round, beige

Pasteurisation immobile slow small round, beige

- nitrogen source

immobile, rods

slow small white, smooth

- nitrogen source + yeast extract

mobile fast large yellow, smooth

+ salt - slow small small, round, white

+ salt + yeast extract

- fast large large, round, white

acidic cocci, immobile

slow small beige, bright

alkaline cocci, immobile

slow small beige, bright

Regina Gohl, K. Noreen Boyle ICBM Uni Oldenburg 7

Summary

•Results as expected•Variety of bacteria in soil•Different treatment growth / no growth

Introduction Aims & Expectations Course results Summary

- nitrogen source + yeast extract

- nitrogen source

Regina Gohl, K. Noreen Boyle ICBM Uni Oldenburg 8

Thank you for your attention