Page 9 - WCBM JAC 2020 Proceeding Book

The 8th WCBM Junior Academic Competition, November 7th, 2020

Figure 6. Growth in the Supernatant of 1, 6, 7

In the MRS cultivated crop bacteria, all strains(b, c, d, e) decreased the growth of other crop bacteria(2, 4, 5, 8,
9, 10, 11, 12) to nearly zero. In contrast, the tested bacteria thrived in MRS, which confirmed that the strains b,
c, d, and e were able to restrain the growth of other strains. The results show that some crop bacteria produce a
substance that represses the growth of other strains.

Figure 7. Growth in the Supernatant of b, c, d, e

4) Change in honey sugar content due to crop bacteria.
The crop plays a key role in maintaining nectar at a good state so that it may be shared with other nestmates.
Thus, the crop bacteria should affect the nectar as little as possible in order to keep the colony healthy. It was
assumed that if the metabolism of bacteria utilized honey, the sugar content would decrease. The 17 crop bacteria
strains were cultured in pure honey and the sugar content was measured.
All 17 strains showed to decrease the honey content. It seemed that as the bacteria metabolized fructose, sugar
levels decreased. Strains 2 and 3 showed to most alter the honey, as they decreased the sugar levels by over 4
brix. Strains 6, 7, 8 showed the least change, diminishing sugar by 1.2, 1.6, and 0.4, respectively.

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