We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. The glass rod is sterilized and used to spread the microbe-containing liquid uniformly on the plate. The solution is then spread uniformly through a number of possible means, the most popular is the use of sterile glass beads that are shook on top of the media, spreading the microbe-containing liquid evenly on the plate.Īlso common is the use of a bent-glass rod, often referred to as a hockey stick, due to its similar shape. They are then transferred to a petri dish with media specific for the growth of the microbe of interest. Growth media are usually forms of agar, a gelatinous substance derived from seaweed.
Samples can then be taken from the resulting colonies and a microbiological culture can be grown on a new plate so that the organism can be identified, studied, or tested.The streaking is done using a sterile tool, such as a cotton swab or commonly an inoculation loop.Ĭhoice of which growth medium is used depends on which microorganism is being cultured, or selected for. The dilution of microbes is very important to get to microbes diluted enough to count on a spread plate (described later). Usually the dilution factor at each step is constant, resulting in a geometric progression of the concentration in a logarithmic fashion.įor a ten-fold dilution on a 1 mL scale, vials are filled with 900 microliters of water or media, and 100 microliters of the stock microbial solution are serially transferred, with thorough mixing after every dilution step. This means passing rims and lids through the flame produced by a Bunsen burner in order to kill microorganisms coming in contact with those surfaces. This requires that exposure of containers of sterilized culture media to outside air should be minimized, and that flame is used to re-sterilize container lids and rims. This technique involves using flame to kill contaminating organisms, and a general mode of operation that minimizes exposure of sterile media and equipment to contaminants.īy Leberechtc (Own work) GFDL ( ) and CC-BY-3.0 ( ), via Wikimedia Commons. Sterile technique should always be employed when working with live cell cultures and reagentsmedia that will be used for such cultures.
#Serial dilution lab report microbiology serial
Serial Dilution Microbiology Lab Report Serial Dilution Experimentsĭavidson, Estimation method for serial dilution experiments, Journal of Microbiological Methods, Volume 107, 2014, Pages 214-221, ISSN 0167-7012. In coffee, we add a certain amount of cold press coffee and add water over it so obtain a desired concentration of coffee. This results in the highest dilution to have the most inaccuracies and the least accuracy. It is believed than dilution increases the potency of the diluted substance by activating its vital energy.
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