Agar PDA e MEA - Preparo de placas de Petri esterilizadas e uso de panela de pressão como autoclave

We present a method for preparing Potato Dextrose Agar (PDA) and Malt Extract Agar (MEA) and their sterilization in a pressure cooker used as an autoclave. 0:00 Introduction 0:38 PDA Agar 6:03 Reagent bottle 4:26 MEA Agar 8:20 Erlenmeyer stopper 8:44 Preparation of Petri dishes 9:56 Chemical and biological test for autoclave 11:16 Pressure cooker as autoclave 14:47 Sterilization results 16:18 Solubilization and remelting of the agar 17:48 Environment preparation 18:38 Flame protection 19:15 Deposition of agar on a sterile plate 21:26 Cultures obtained Methodology 200 mL of PDA agar: 0.8 g of potato starch; 4 g of powdered glucose (or 4.5 g of "liquid" glucose); 3 g of good quality agar; 200 mL of treated water (preferably distilled); Add the solid components and add the water, stir until homogenized and gently heat to 85-95°C until the agar is melted. The agar can be left to melt during autoclaving. In the latter case, the mixture should be homogenized after autoclaving. PS: The water and potato starch can be replaced with 200 mL of potato infusion (infusion of 40 g of potatoes for every 200 mL of water); 200 mL of DME: 6 g of dry malt extract - (Preferably DME, "light" type) 4 g of good quality Kanten agar; 200 mL of treated water (preferably distilled); Add the solid components and then the water, stir until homogeneous, and gently heat to 85-95°C until the agar melts. Alternatively, the agar can melt during autoclaving. In this latter case, the mixture should be homogenized after autoclaving. We suggest sterilization in a pressure cooker for 60 minutes, as this time has proven sufficient for the inactivation of spores of the microorganism Geobacillus stearothermophilus. If a very large quantity of material needs sterilization, we recommend 90 minutes of autoclaving. It is important to remember to put enough water in the pressure cooker to ensure steam throughout this time. Using a Bunsen burner flame allows for the creation of a much larger safe area than a spirit lamp. A laminar flow hood to prevent contamination of sterilized material by the environment is much more efficient and easier to handle than flame protection. Music: Journey in the New World by Twin Musicom is licensed under a Creative Commons Attribution license. Source: http://www.twinmusicom.org/song/258/j... Artist: http://www.twinmusicom.org References 1. BACTERIOLOGICAL ANALYTICAL MANUAL, 8th Edition, Revision A, 1998. BAM Media M127: Potato Dextrose Agar. Available at: https://www.fda.gov/food/laboratory-m... 2. COMMITTEE ON BACTERIOLOGICAL TECHNIC. Manual of microbiological methods by American Society for Microbiology. New York: McGraw-Hill Book Company, Inc, 1957. 315 p. 3. GUTZ, Herbert; DOE, Frank J. TWO DIFFERENT h - MATING TYPES IN SCHIZOSACCHAROMYCES POMBE. Genetics, [S.L.], v. 74, no. 4, p. 563-569, 1 Aug. 1973. Oxford University Press (OUP). http://dx.doi.org/10.1093/genetics/74.... 4. BACTERIOLOGICAL ANALYTICAL MANUAL, 8th Edition, Revision A, 1998. BAM Media M93: Malt Extract Agar. Available at: https://www.fda.gov/food/laboratory-m... 5. ATKINS, Peter; PAULA, Julio de. Physical Chemistry: vol. 1. 9th ed. Rio de Janeiro: LTC, 2013. 416 p. Translation and technical review by Edilson Clemente da Silva, Márcio José Estillac de Mello Cardoso, Oswaldo Esteves Barcia. 6. Maquira Biological Test Manual, available at: https://maquira.com.br/wp-content/upl... 7. WHITMAN, David A.; READ, David M.; PARTHASARATHY, Ranjani V.; LANDGREBE, Kevin D.; BENNETT, Anthony E. CHEMICAL INDICATOR COMPOSITIONS, INDICATORS AND METHODS. Applicant: 3M Innovative Properties Company. US No. 2011/0312096 A1. Filing Date: June 15, 2011. Grant Date: December 22, 2011. Available at: https://www.freepatentsonline.com/RE3... 8. FOLEY, Theodore A. STEAM STERILIZATION INDICATOR. Applicant: Pymah Corporation. Attorneys: Robert H. Falk and Tom R. Vestal. US No. 34,515. Filing Date: December 24, 1991. Grant Date: January 18, 1994. Reissue of US Patent 4,448,548. Available at: https://www.freepatentsonline.com/201... 9. WHITE, Chris; ZAINASHEFF, Jamil. Yeast: the practical guide to beer fermentation. Boulder: Brewers Publications, 2010. 304 p. 10. PETRI, Julius Richard. Eine kleine Modification des Koch'schen Plattenverfahrens. Centralblatt Für Bakteriologie Und Parasitenkunde, Berlin, v. 1, p. 279-280, Feb. 1887. Available at: https://www.biodiversitylibrary.org/i... 11. VERMELHO, Alane Beatriz; PEREIRA, Antônio; COELHO, Rosalie; SOUTO-PADRÓN, Thaïs. Práticas de microbiologia. 2nd ed. Rio de Janeiro: Guanabara Koogan, 2019. 256 p. #ChemistryCommunity #Microbiology #PDAagar