Explanation: Kirsop and Doyle in 1991 gave the full details of the preservation techniques. The preservation techniques were used to store the microbial culture for a longer period of time.

Explanation: The techniques of preservation include – storage on agar slants, storage under liquid nitrogen, dried cultures, lyophilization. Storage in water is not a technique for the preservation of microbes.

Explanation: The agar slants can be covered by paraffin oil and the extension time can be increased from 6 months to 1 year. DMSO, Glycerol, Loamy soil are used in the preservation techniques for the preservation of microbes more than decades.

Explanation: The temperature of liquid nitrogen is -196°C. It is used to store and preserve the microbial culture for a decade or even more. The cryoprotectants are added to the culture suspension before adding to liquid nitrogen.

Explanation: The cryoprotective agents like DMSO, 10% Glycerol, Glycol are the agents that are added to microbial cell culture to protect the cells at a lower temperature or in liquid nitrogen at -196°C.

Explanation: The preservation by liquid Nitrogen is called as Cryopreservation. The cryoprotective agents are added to the culture before preservation, hence the name, Cryopreservation.

Explanation: Lyophilization is the method that is based on freezing of culture followed by drying under vacuum. This is known as sublimation. It is useful for the storage or preservation of culture for more about 25 years.

Explanation: Lincoln in 1960 outlined the statement “Each batch of newly preserved cultures should be routinely checked to ensure their quality” for quality control of preserved stock cultures.

Explanation: The use of sand and soil in dried culture preservation is that it reduces the metabolic activity of the culture and also doesn’t allow oxygen to diffuse.

Explanation: The cultures grown on agar slopes may be stored in the refrigerator or freezer at 5°C to -20°C and sub-cultured at approximately 6-monthly intervals.

Explanation: The processing and the handling time in lyophilization are more as there are many incubation periods, thus a time-consuming process. Handling and processing time is a major disadvantage of lyophilization.

Explanation: The main function of cryoprotective agents is to prevent cell damage for the preservation of microbial cell culture in liquid nitrogen at -196°C.

Explanation: The preservation of microbial cell culture does not alter the metabolism of microbes. Metabolism continues. The microbial culture is active viably and dividing during the preservation.

Explanation: Lyophilization is the process of freeze-drying which involves sublimation of cell water and can be used to store culture for about 25 years.

Explanation: The nutrient agar plates contain yeast/beef extract, peptone, NaCl and Agar-Agar Powder. Dextrose is constituent of Potato Dextrose Agar.