Effect of different physical conditions on nitrogen fixing bacteria from rhizosphere
Hypothesis:
Rhizospheric Nitrogen fixing bacteria show optimal growth at PH: 6-7, Temperature: 30 °C and Salinity level: 0.005 – 0.010M NaCl
INTRODUCTION: There is a huge bacterial diversity in rhizospheric soil. Gram-negative, non-sporulating baccilli which respond to root exudates are predominant in the rhizosphere (Pseudomonas, Agrobacterium). While Gram-positive bacilli, Cocci and aerobic spore forming bacteria like Bacillus and Clostridium are rare in the rhizosphere. The most common genera of bacteria are Pseudomonas, Arthrobacterm Mycobacterium, Flavobacter, Cellulomonas, Agrobacterium, Alcaligenes, Azotobacter,
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We took 2 Petri plates containing L-agar and spread 50µl from dilutions 〖10〗^(-3) and 〖10〗^(-5) respectively on L-agar plates by using spreader and incubated them at 37°C for 24 hours. After 24 hours incubation, we selected isolated colony and streak it on L-agar containingPetri plates to purify it.
After 24 hours incubation, we got our purified colony, now we checked either it is nitrogen fixing bacteria or not, for this purpose we performed “Nitrite Detection Test”.
Nitrite Detection Test: We made mother culture of our strain. We took 3 test tubes and added 3 ml ammonium sulphate broth and autoclaved them. Then labelled them as +ve control, -ve control and test. In +ve control, we added 0.1 gram soil, in –ve control,we didn’t add anything and in 3rd test tube we added 0.1ml from mother culture. We incubated all of them at 37°C for 7 days. We took slide and divided it into 3 portions and labelled as +ve, -ve and test. And placed one drop from each test tube on slide. Now added one drop of Trommosdrof reagent on each three sites and checked results.
Interpretation:
No color -------- -ve
Catalase Activity on Substrate Based On Gas Pressure Production Rate Name of the Class Author’s Name Date Enzymes are organic compounds which act as catalysts and speed up biological reactions in biological organisms. They are not destroyed or changed during the reaction but rather they are used over and over again to catalyze many more reactions. Their activity may be affected and altered by factors such as temperature, substrate concentration, enzyme concentration and Ph.
After 5 days the plates were removed from the cold room and the gram-negative test for Colony A on the EMB agar showed pink fisheye colonies which lead to the conclusion that the gram-negative organism within Unknown #21 was Enterobacter aerogenes. Had the pigmentation been metallic green, the organism would have been identified as Escherichia coli, and had there been no pigmentation at all a Triple Sugar Iron agar (TSI) test among other tests would have been
The purpose of this lab report is to employ a myriad of skills, tools and, methods learned throughout this semester to perform the appropriate tests for the identification of the assigned unknown bacteria. Add more background information here!!! The most important tools and techniques used during this identification include aseptic technique, microscopic examination and, the use of selective and differential media. Aseptic technique is an important tool for microbiologists. It is imperative that aseptic technique is maintained throughout the length of any test to avoid any cross-contamination that may lead to inaccurate results.
I expect to learn the biochemical differences in bacteria from this lab. Also, how to identify different species of bacteria. Material & Methods For the first day of the practical, an unknown specimen was provided
Bacteria convert nitrogen gases into ammonium, which allows nitration to turn ammonium into nitrates. Go to the web site: http://www.studystack.com/matching-1457 1. Do the nitrogen cycle quiz. Go to the web site: http://www.nodvin.net/snhu/SCI219/demos/Chapter_3/Chapter_03/Present/animations/32_2_1a.html 1. Why is nitrogen such a critical nutrient?
The tube was placed back in incubation for 96 more hours to observe any more positives. 2.10 Catalase Test A trypticase soy agar plate was used and after incubation, four drops of 3% Hydrogen Peroxide was added to the plate to flow over the bacterial growth. A presence of bubbling was observed. 2.11 Starch Hydrolysis
The gram negative species are apart of the Enterobacteriaceae family. These are gram-negative rods, which are facultatively aerobic - either respiring or fermenting. Most are motile via a flagella (Carson, 2015). Salmonella enterica and Yersinia enterocolitica are both paracolons, which lack the ability to ferment lactose. Conversely, Klebsiella pneumoniae and Escherichia coli are both coliforms, which are able to ferment lactose.
The unknown bacteria was then tested on multiple selective and differential media. Growth was present on the MacConkey Agar and the colonies were the same color as the plate, which told me my bacteria was gram negative and did not ferment lactose. There was no growth on the Mannitol Salt Agar, and this told me the unknown was not salt tolerant and did not
By Gram staining alone, it was safe to eliminate the three Gram positive bacteria that could have been assigned: S. epidermidis, M. luteus, and B. megaterium. The second step was to streak plate Unknown #10 to observe its macroscopic
According to the series of test that my group ran for our unknown specimen, we had a match with the bacteria known as Alcaligenes Faecalis. This bacterium belongs to one of the major group of gram-negative bacteria (Phylum Proteobacteria). Alcaligenes Faecalis (Genus, species) is a rod shaped (bacillus), 0.5-1.2 x 1.0-3.0 µm, round with scalloped margin (colony configuration growth), motile (with one to nine peritrichous flagella), gram-negative, non-fermentative bacteria, obligate aerobic, having oxygen as the principal terminal electron acceptor in the electron transport chain (ETC). We consider we have a match with the species Alcaligenes Faecalis because of the following reasons: Fermentation tests performed (Durham sugars) were negative, which indicate that our bacteria use a different metabolic means for growth (non-fermentative gram-negative bacteria).
Exercise 14: Unknown Identification Lab Report The purpose of the study was to identify the unknown bacterium using various biochemical tests in addition to using scientific methods in determining the outcome of the hypothesis. Each biochemical test will help determine the bacteria based on specific characteristics of each organism. I was giving unknown number 232. The first procedure that needed to be done after obtaining unknown bacterial mixture was to isolate the two bacteria in a pure culture using the streak plate method described in Microbiology Laboratory Manual Eight Edition. The material used was trypticase soy agar (TSA) plate, nutrient plate, starch agar, hydrogen peroxide, iodine reagent and microscope.
The B. Vulgaris samples were approximately 1cm3. They were kept the same size to ensure accurate results. A control test was conducted in distilled water to obtain a result to compare. The ethanol treatments were 40% and 70%. To prepare the solutions a 70% ethanol solution was used to make 40%.
Do the same for the other test tubes. Let the test tubes not be disturbed for about 3- 4 mins. Then add the Amylase solution to the Starch solution and start the stopwatch (immediately). After every 1 min take one drop from the test tubes and place then in the test plate that were
From the Unknown tube professor Cooper gave me, I scratched a little on the slant surface with the sterilized inoculating loop. Then I place it on a clean prepared slide which already had a slight drop of water. The two substances are mixed together in the middle of the slide and let dry completely. One extra step of “heat fix” is necessary to adhere everything to the surface of the slide. To start gram staining, I slightly pour crystal-violet all over the slide and let it sit for 30 seconds before wash it off with water.
Some denitrifying bacteria include species in the genera Bacillus, Paracoccus, and Pseudomonas. Denitrifiers are chemoorganotrophs and thus must also be supplied with some form of organic carbon. Denitrification is important in that it removes fixed nitrogen (i.e., nitrate) from the ecosystem and returns it to the atmosphere in a biologically inert form