FUNDAMENTALS OF MICROBIOLOGY CIVL270-Maraqa Environmental Applications of Microbial Processes Wastewater treatment aerobic/anaerobic Industry Biocatalysts (enzymes) Fermentation (cheese, yogurt, pickles) Pharmaceuticals (antibiotics) Bioremediation Contaminated groundwater Land-farming Microorganism Size (um) Viruses 0.02-0.3 Bacteria 0.1-10 Some are pathogenic Cholera, typhoid Algae 1-100 Non pathogenic Fungi Few umseveral cm Protozoa 10-300 CIVL270-Maraqa Disease All pathogenic AIDS, hepatitis, mad cow Many are nonpathogenic Some are pathogenic Amebic dysentery, malaria CIVL270-Maraqa Coliform as an Indicator Total coliform coliform Total Fecal Fecal Nonfecal Nonfecal Membrane Filter Technique CIVL270-Maraqa 35 oC 44.5 oC Multiple-Tube Fermentation Technique CIVL270-Maraqa No of tubes giving positive reactions out of MPN Index for Coliform Counts by the Multiple-Tube Fermentation Technique MPN index of 10 ml each of ml each of 0.1 ml each per 100 ml 33 4 34 0 23 31 43 70 110 140 3 180 130 5 >2400 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 membranes for each sample volume The number of colonies on each filter after incubation is listed below Find the number of coliforms/100 ml Solution: Filter #1 #2 #3 5-ml portion 50-ml portion 24 32 25 200-ml portion 101 128 144 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 CIVL270-Maraqa In-Class Exercise A multiple tube fermentation analysis of river water yielded the following results What is the MPN/100 ml of the water? Solution: Serial dilution Sample portion (ml) + tubes out of 1.0 0.1 0.01 0.001 0.0001 We choose 5-2-1 From the MPN table we have 70/100 ml To account for dilution we have 70 (10/0.1) = 7000/100 ml of river water