CEE 467 – ENVIRONMENTAL MICROBIOLOGY
NAME: ERICK PEREIRA DANTAS
DATE: SEPTEMBER 4th, 2014
PROFESSOR: DR. MORTEZA ABBASZADEGAN
TA: LAUREN MCBURNETT
LABORATORY #2 – BACTERIOLOGICAL EXAMINATION OF WATER: MOST PROBABLE NUMBER TEST AND MEMBRANE FILTRATION METHOD
ABSTRACT: The most probable number (MPN) test and the membrane filter (MF) method have as goal to detect and estimate the presence of coliforms in a sample. Their importance in the field of environmental engineering is to support the start of the analysis for possible biological contamination in water for causative microorganisms of waterborne disease. For they use coliforms they are cheaper and faster than others. This experiment had positive results. The colonies were counted …show more content…
The gas generation is due to E. coli metabolic processes that generates acid and changing the turbidity. 2. The Membrane Filtration Method did work as well. MF method can replace the MNP test for microbiological analysis of water sample. After the incubation of the mEndo plate for 24 hours it is perceptible the grown of E. coli colonies across the plate. The results of this method are shown in the figure 4. As it was used mEndo, just the E. coli colonies form bright green colonies with a golden or green sheen - and it is evident in the plate, and the colonies which are not within of this specific characteristic are not considered E. coli. Next, it is necessary to count the E. coli colonies that grown in the plate. In this experiment, 450 colonies of E. coli were counted, and the results are frequently reported as colony forming units (CFU) per 100 ml of sample. Considering that the amount of water used was 100 ml, in other words 100 % of 100 ml or 1. The result is obtained multiplying numbers of counted E. coli colonies by the percentage of water used. That is to say, the result of this test is 450 …show more content…
coli to be cheaper and faster than the usage of other microorganisms. Their results are used to start the investigation for causative pathogens of waterborne and to ensure that drinking water is completely safe to consumption. Fortunately, positive results were attained indicating fecal contamination and possible presence of other microorganism. Finally, the cause of the success in this experiment is:
• The procedures were correctly followed, resulting in positive-coliform in both tests. MNP had 460 CFU/ml of E. coli, and MF 450 CFU/ml of E. coli. In the MNP test was perceptible the production of gas and high turbidity due acid generation by the coliforms metabolism favored by the medium contained lactose. In the MF test was noticeable the growth of E. coli colonies identified by their bright green color due the environment (mEndo). In summary, the average result of this experiment is 455 CFU/ml of coliforms showing the fecal contamination. Concisely, these types of analysis are extremely essential to environmental investigations, in view of, they must ensure that water are properly within of standards according to
NAME: ERICK PEREIRA DANTAS
DATE: SEPTEMBER 4th, 2014
PROFESSOR: DR. MORTEZA ABBASZADEGAN
TA: LAUREN MCBURNETT
LABORATORY #2 – BACTERIOLOGICAL EXAMINATION OF WATER: MOST PROBABLE NUMBER TEST AND MEMBRANE FILTRATION METHOD
ABSTRACT: The most probable number (MPN) test and the membrane filter (MF) method have as goal to detect and estimate the presence of coliforms in a sample. Their importance in the field of environmental engineering is to support the start of the analysis for possible biological contamination in water for causative microorganisms of waterborne disease. For they use coliforms they are cheaper and faster than others. This experiment had positive results. The colonies were counted …show more content…
The gas generation is due to E. coli metabolic processes that generates acid and changing the turbidity. 2. The Membrane Filtration Method did work as well. MF method can replace the MNP test for microbiological analysis of water sample. After the incubation of the mEndo plate for 24 hours it is perceptible the grown of E. coli colonies across the plate. The results of this method are shown in the figure 4. As it was used mEndo, just the E. coli colonies form bright green colonies with a golden or green sheen - and it is evident in the plate, and the colonies which are not within of this specific characteristic are not considered E. coli. Next, it is necessary to count the E. coli colonies that grown in the plate. In this experiment, 450 colonies of E. coli were counted, and the results are frequently reported as colony forming units (CFU) per 100 ml of sample. Considering that the amount of water used was 100 ml, in other words 100 % of 100 ml or 1. The result is obtained multiplying numbers of counted E. coli colonies by the percentage of water used. That is to say, the result of this test is 450 …show more content…
coli to be cheaper and faster than the usage of other microorganisms. Their results are used to start the investigation for causative pathogens of waterborne and to ensure that drinking water is completely safe to consumption. Fortunately, positive results were attained indicating fecal contamination and possible presence of other microorganism. Finally, the cause of the success in this experiment is:
• The procedures were correctly followed, resulting in positive-coliform in both tests. MNP had 460 CFU/ml of E. coli, and MF 450 CFU/ml of E. coli. In the MNP test was perceptible the production of gas and high turbidity due acid generation by the coliforms metabolism favored by the medium contained lactose. In the MF test was noticeable the growth of E. coli colonies identified by their bright green color due the environment (mEndo). In summary, the average result of this experiment is 455 CFU/ml of coliforms showing the fecal contamination. Concisely, these types of analysis are extremely essential to environmental investigations, in view of, they must ensure that water are properly within of standards according to