Final answer:
UV radiation is used for sterilizing thermolabile liquids like urea broth and for air purification in biological safety cabinets, as it does not involve high temperatures that could degrade sensitive materials, unlike autoclaving which uses moist heat.
Step-by-step explanation:
Sterilization Methods for Thermolabile Liquids
UV radiation is the method used to sterilize liquids that are thermolabile, such as urea broth. This type of sterilization is also employed to clean air in biological safety cabinets, operating rooms, isolation units, and various other environments where maintaining sterility is essential. Unlike autoclaving, which employs moist heat to sterilize and is effective against a broad range of microorganisms including endospores, UV radiation is used for heat-sensitive materials, as it does not involve high temperatures that could degrade the product. UV light is effective in deactivating bacteria, viruses, and other pathogens by damaging their DNA and RNA, making it impossible for the microorganisms to replicate and cause infection. Laboratories often utilize UV lamps in biological safety cabinets to maintain a sterile environment for the manipulation of microorganisms.
Other sterilization methods like ionizing radiation (including gamma irradiation) and lyophilization have their specific applications for preserving or sterilizing heat-sensitive materials but are not the primary focus for sterilizing thermolabile liquids or cleaning air in safety cabinets. While UV radiation cannot penetrate surfaces and is therefore limited to surface disinfection, it remains a suitable choice for treating air and delicate liquids in specialized settings.