To grow fungi in a lab, lift the cover of a sterile agar dish only enough to insert a small block of agar containing the desired fungi, face down, in the center of the dish. Most fungi thrive at room temperature (approximately 25°C).
That's the simple answer, but here's a bit more information to help you be successful:
Key Steps in Fungal Cultivation:
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Sterilization: This is the most critical step. Everything that comes into contact with your culture (agar, tools, containers) must be sterile to prevent contamination from other microorganisms like bacteria or unwanted fungi. Autoclaving is the most common method.
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Media Preparation: Fungi need nutrients to grow. Agar plates are commonly used. The agar is mixed with nutrients (e.g., potato dextrose agar (PDA), malt extract agar (MEA)) and then sterilized. These nutrient sources provide carbohydrates and other essential elements.
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Inoculation: This is the process of introducing the desired fungal spores or mycelium (the vegetative part of the fungus) to the sterile agar plate. In the provided answer, the instruction is to insert a block of agar already containing the fungus. When starting from spores, a sterile loop is used to transfer spores to the agar surface. This must be done in a sterile environment, such as a laminar flow hood, if available.
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Incubation: After inoculation, the agar plates are sealed (e.g., with parafilm) to prevent contamination and desiccation and placed in a temperature-controlled environment. As mentioned, most fungi grow well at room temperature (around 25°C). However, the optimal temperature can vary depending on the specific fungal species.
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Observation and Maintenance: Regularly observe the plates for fungal growth and any signs of contamination. If contamination occurs, the plate should be discarded properly. Subculturing (transferring a portion of the growing fungus to a new sterile plate) may be necessary to maintain a pure culture.
Important Considerations:
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Aseptic Technique: Strict adherence to aseptic technique is essential throughout the entire process to prevent contamination. This includes washing hands thoroughly, wearing gloves, and working in a clean environment.
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Nutrient Media: Different fungi have different nutritional requirements. Choose the appropriate nutrient media based on the specific fungal species you are trying to cultivate. PDA and MEA are common general-purpose media.
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Temperature and Humidity: Maintain the optimal temperature and humidity levels for the specific fungal species.
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Lighting: While not always critical, some fungi require light for sporulation (spore formation).
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Safety: Be aware of the potential hazards of working with fungi. Some fungi are pathogenic (disease-causing) and require special handling precautions. Work under a biological safety cabinet is recommended when handling pathogenic fungi. Discard contaminated cultures properly, typically by autoclaving before disposal.
