Our genomic library preparation kit finally came in (about a week late) but neither of the mentors are around to explain how to use it, so I thought I’d do some research and see what I could find on the Microbacterium genus. Unfortunately, most Google results are for the Mycobacterium genus which, while a very fascinating genus I’m sure, does not help me at all.
I finally came across a study performed in the mid 1960′s which analyzed some characteristics of the Microbacterium genus. The term Microbacterium was proposed in the early 20th century to identify a particular group of very small, gram-positive, rod-shaped bacteria that have been found in many dairy products. An important characteristic of Microbacterium species is that they are unusually heat resistant. The researchers conducted a number of tests to learn more about the physiological characteristics of the genus, based on 25 unique strains.
Particularly of interest to me is the following:
- These bacteria grow aerobically, but some strains can grow under anaerobic conditions. However, they divide much more slowly and lack pigmentation when grown anaerobically. Each strain in the study grew at a decent rate (typically around 3 days of incubation, but as much as 7 days were needed in some cases) when incubated in the 30-37 degree C range. Only 5 strains grew at 39 degrees and only 3 strains grew at 9 degrees.
- All strains grew in mediums with a pH of 6.8 and 7.5 . More acidic conditions (pH < 6) yielded almost no growth from the strains.
- Some members of the genus have the ability to reduce nitrates and liquefy casein, while nearly every strain could hydrolyze gelatin
- 5 strains were able to withstand 85 degree heat, and every strain was able to withstand at least 60 degree heat
- There is doubt as t0 where this genus should be placed in a phylogenetic tree. At the time of publication of this study, the most recent proposal was to place Microbacterium within the Corynebacterium. The author, however, dismissed this based on what he observed in terms of heat resistance and ability to be cultured, noting large differences between the two.
Here is a link to the paper