Microbiology: a very short introduction

Environmental Applications of Microbial Processes  Industry Biocatalysts enzymes Fermentation cheese, yogurt, pickles Pharmaceuticals antibiotics  Bioremediation Contaminated ground

FUNDAMENTALS OF

MICROBIOLOGY

Environmental Applications of

Microbial Processes

 Industry

Biocatalysts (enzymes) Fermentation (cheese, yogurt, pickles) Pharmaceuticals (antibiotics)

 Bioremediation

Contaminated groundwater Land-farming

Viruses 0.02-0.3 All pathogenic

AIDS, hepatitis, mad cow Bacteria 0.1-10 Some are pathogenic

Cholera, typhoid Algae 1-100 Non pathogenic

Fungi Few

um-several cm Many are nonpathogenic Protozoa 10-300 Some are pathogenic

Amebic dysentery, malaria

CIVL270-Maraqa

 Membrane Filter

Technique

Coliform as an Indicator

Total coliform

Fecal Nonfecal

35 o C

44.5 o C

CIVL270-Maraqa

MPN Index for

Coliform Counts by

the Multiple-Tube

Fermentation

Technique

No of tubes giving positive

5 of 10

In-Class Exercise

The membrane filter method is used to test a water for

coliform Three different sample volumes (5, 50, and 200 ml) were filtered through 3 membranes for each sample volume The number of colonies on each filter after incubation is listed below Find the number of coliforms/100 ml.

5-ml portion 4 8 5 50-ml portion 24 32 25

200-ml portion 101 128 144

Solution:

Use the 50-ml portions since the counts fall between 20-80 Average of 24, 32, and 25 is 27 coliform/50 ml.

In a 100-ml sample we have 27 x (100/50) = 54/100 ml.

In-Class Exercise

A multiple tube fermentation analysis of river water yielded the following results What is the MPN/100 ml of the water?

Serial dilution portion (ml) Sample + tubes out of 5

Solution:

We choose 5-2-1

From the MPN table we have 70/100 ml