Entry ni ditujukan kepada ahli2 mikrobiologi terutamanya mikrobiologist Lab 3159 (Microbiologist lab lain pun bole jugak..sile jgn kecik hati).. Seperti yang diarahkan oleh datin kita.. kita dikehendaki menyelamatkan bakteri-bakteri dengan ape cara sekalipun. So di sini ade info sikit psl preservation bakteri2 kite itu.. (aishh..terikut2 perkataan kak yuyun..huhu).. Info terjumpa dalam e-book microbe td..
The Preservation of Microorganism
■ The simplest procedure is to transfer cultures periodically to fresh solid slants of agar in the appropriate medium and to incubate them at a suitable growth temperature. Once the slant cultures are well established, they are kept in a refrigerator at 5◦C enclosed in a container to avoid desiccation. This is the least expensive procedure and keeps cells viable for many months, but there is a danger that mutants or contaminants may accumulate in such cultures.
■ Lyophilization (freeze-drying) is a particularly convenient preservation method. Microbial cells are mixed with a medium containing skim milk powder (at 20% w/v) or sucrose (at 12% w/v) and frozen, after which the water is removed from them by sublimation under partial vacuum. Lyophilized samples remain viable for many years and can be shipped without refrigeration.
■ Cells can be stored for prolonged periods of time at liquid nitrogen temperature. In this procedure, the cells are placed in ampules with media containing (by volume) either 10% glycerol or 5% dimethylsulfoxide and are slowly frozen; their temperature is decreased by 1◦C to 2◦C per minute until it reaches about −50◦C. The ampules are then stored at −156◦C to −196◦C in a liquid nitrogen refrigerator. Additives such as skim milk, sucrose, glycerol, and dimethylsulfoxide minimize damage to the cells by preventing ice crystals from forming during the freezing process.
■ Many spore-forming bacteria and fungi can be preserved by slowly airdrying the spores at ambient temperature on the surface of sterilized soil, silica gel, or glass beads.
sumber: Glazer, Microbial Biotechnology, Fundamentals of Applied Microbiology.
p/s::aku je yg xselamatkan lg bakteria aku..kena selamatkan segera!