Final answer:
Capnophiles are bacteria that grow best in high CO2 and low oxygen conditions. A candle jar is a typical method used to provide such an environment in the lab, allowing these organisms to be cultured effectively by altering the atmosphere to their preference.
Step-by-step explanation:
Capnophiles are bacteria that require higher concentrations of carbon dioxide (CO2) for optimal growth compared to what is present in the atmosphere. These organisms often grow in conditions where oxygen levels are lower. To culture these organisms in a laboratory, one commonly used method is employing a candle jar. This involves placing the cultures in a jar along with a lit candle, then sealing the jar with a tight-fitting lid. As the candle burns, it consumes oxygen and produces CO2, creating an environment suitable for the growth of capnophiles. Aside from capnophiles, there are other categories of extremophiles with unique growth requirements. For instance, barophiles flourish under high hydrostatic pressure, such as those found at the depths of the ocean. Methanogens produce methane as a metabolic byproduct, while thermophiles and hyperthermophiles prefer extremely high temperatures. Each of these extremophiles has adaptations that enable them to thrive under conditions that would be inhospitable for other organisms.