THE SCHOOL OF SCIENCE, ENGINEERING, AND HEALTH
DEPARTMENT OF SCIENCE & ENGINEERING
BMS 304: MEDICAL MYCOLOGY JAN 2023
CHRISTELLE OUEDRAOGO 21-0607
REPORT ON PREPARING CULTURE
SUBMITTED TO
DR MONICA OPIYO
EXPERIMENT ONE: PREPARING CULTURE
INTRODUCTION
Fungi culture media are required for fungus development and upkeep in the laboratory.
Depending on the investigation, these substances can be either solid or liquid. These
substrates are intended to provide the nutrients, pH, and other factors essential for the
development of various kinds of fungi. Most fungus thrive in medium with a rich
carbohydrate source, a nitrogen source, a pH of 5-6, and a temperature range of 15-37
degrees Celsius. Because no medium can support the development of every fungal species,
the medium on which a fungus develops will differ from species to species. Some fungi, such
as downy mildews, cannot be grown in vitro and must rely on their plant host to live.
OBJECTIVES
To prepare Potato Dextrose Agar media and Sabouraud Dextrose Agar
To weight the media using the balance
To melt the agar media following instructions on the bottles
To sterilize by autoclaving for 15 min at 121°C
To observe the fungi growth
REAGENTS & MATERIALS
1. Potato Dextrose Agar
2. Saborounds Dextrose Agar
3. Flask
4. Distilled water
5. Stirrer
PROCEDURE
I-Saborounds Dextrose Agar
1. Suspend 65g of the agar medium in 1 litre of distilled water
2. Combine all ingredients in ~900 ml of deioinized water.
3. Adjust to pH 5.6 with hydrochloric acid and adjust final volume to 1 liter.
4. Heat to boiling to dissolve the medium completely.
5. Autoclave at 121ºC for 15 minutes.
6. Cool to ~45 to 50°C and pour into petri dishes or tubes for slants.
7. Streak using wire loop colony of yeast fungi onto the plate
8. Place in the incubator at 37oC and check colony growth after 48 hrs for fungal
colonies
9. Ensure you have before and after pictures and pictures of all the set up
II-Potato Dextrose Agar
1. Suspend 39 g/l. Autoclave (15 min at 121 C).
2. The appearance of the plates is clear and yellowish-brown.
3. The pH value at 25 °C is in the range of 5.4-5.8.
4. If the pH has to be adjusted to 3.5, add approx. 14 ml of a sterile 10 % tartaric acid
solution/l at a temperature of 45-50 °C. After the tataric acid is added, do not
reliquefy.
5. Streak using wire loop colony of yeast fungi onto the plate
6. Place in the incubator at 37oC and check colony growth after 48 hrs for fungal
colonies
7. Ensure you have pictures of the entire process showing set up and before and after
RESULTS
Sabouraud Dextrose Agar Media preparation
Potato Dextrose Agar preparation
Autoclaving part
Inoculation of the fungi on the Sabouraud Dextrose Agar (SBA) and Potato
Dextrose Agar (PA)
The media before incubation
After incubation at 37°c for 24 hours
DISCUSSION
The preparation of Sabouraud Dextrose and Potato Dextrose Agar plate culture media was
the one objective of this study. Many precautionary measures had to be made during the
preparation of growth medium. This was done to ensure that the nutrient content was accurate
so that the fungus could develop properly inside the culture medium.
Sabouraud Dextrose Agar is a selective and differential culture medium that is commonly
used for the isolation and cultivation of fungi. The medium contains two main components:
dextrose (glucose) and peptone. Dextrose provides a source of carbohydrate for the fungi,
while peptone provides amino acids and other nutrients that support fungal growth. The pH
of SDA is typically adjusted to around 5.6, which creates a slightly acidic environment that is
optimal for the growth of fungi. The medium is usually prepared as a solid agar, which allows
fungal colonies to grow and spread across the surface of the medium.
When fungi are grown on a culture medium, they can form visible colonies that can vary in
size, shape, color, and texture. These colonies represent a group of fungal cells that have
grown and multiplied on the surface of the culture medium. Based on the results, the colonies
appeared White to cream, yellowish,
Potato dextrose agar (PA) is a culture medium commonly used for growing fungi in
laboratory settings. PA contains a combination of mashed potatoes, dextrose (a type of
sugar), and agar (a solidifying agent) that provides a nutrient-rich environment for fungal
growth. PA is a versatile medium that supports the growth of a wide range of fungi, including
yeasts, molds, and filamentous fungi. The high nutrient content of PA makes it particularly
useful for isolating and identifying fungal species from environmental samples.
When fungi are grown on PA, they typically form colonies that can vary in color, texture, and
morphology depending on the species of fungus. Some fungi may grow as fluffy, cotton-like
masses, while others may form dense, opaque colonies. The color of fungal colonies on PA
can range from white, yellow, orange, pink, brown, or black, depending on the species of
fungus. According to the results obtained, the colonies appeared pasty opaque slightly
domed, smooth, creamy, and white and domed.
CONCLUSION
Preparing fungi culture media is an essential step in laboratory studies of fungi. There are
many different types of culture media that can be used for growing fungi, each with its own
specific advantages and limitations. In this experiment, Sabouraud Dextrose Agar and Potato
Dextrose Agar were prepared. These media contain a combination of nutrients that provide a
rich environment for fungal growth and development. The growth of fungi on culture media
can provide valuable information for identifying the species of fungus present, testing the
susceptibility of the fungus to different antifungal medications, and studying the growth and
development of fungi under different conditions.
REFERENCES
Aryal, S. (2019, October 13). Potato Dextrose Agar (PDA)- Principle, Uses,
Procedure & Characteristics. Microbiology Info.com.
Morphologic Features of Yeast Colonies - LabCE.com, Laboratory Continuing
Education. (n.d.). Www.labce.com.
Aryal, S. (2019, June 14). Sabouraud Dextrose Agar (SDA) - Principle, Uses and
Colony Morphology. Microbiology Info.com.
Gladwin, M. (2013). Clinical Microbiology Made Ridiculously Simple. Medmaster.
