Abstract:
This study was conducted in Pasir Akar, Pulau Redang. The objectives of this study are
to isolate and identify the types of bacteria present in healthy and bleached tissue of
Acropora sp. Fragments of healthy and bleached Acropora formosa and A.nobilis corals
were taken at the depth of l O m with the aids of scuba gear and brought back to the
laboratory for further analysis and identification. Culture-based methods were applied to
isolate the bacteria from the coral tissues and identified by referring to Bergey's Manual
of Determinative Bacteriology. Overall, there were 23 types of bacteria that had been
successfully isolated and identified. Aformosa was found to harbor 13 types of bacteria;
four from healthy coral colony and nine from bleached coral colony. Meanwhile for
A.nobilis, 10 types of bacteria were to associate with its tissue; six from healthy colony
and four from bleached colony. Some examples of bacteria that had been successfully
identified include Alcaligenes sp., Azotobacter sp., and Micrococcus sp. However, there
is overlapping of bacteria existence where Pseudomonas sp. and Brochothrix sp. are
inhabit both of Aformosa and A.nobilis. All of the bacteria were known to inhabit marine
environment except Acetobacterium sp. and Caryophanon sp. About 62% of the bacteria
are Gram-positive and 38% are Gram-negative. The most dominant groups are affiliated
to y-proteobacteria class and Firmicutes which represent 33% of the total bacteria
isolated respectively, and then followed by Actinobacteria (19%), a-proteobacteria (10%)
and lastly b-proteobacteria (5%). Some of the bacteria may play important roles in the
interaction of coral-bacteria such as nitrogen fixer and secrete antibiotic substances to
xii protect their host, which were the corals itself. However, the overall roles played by these
bacterial communities are still relatively unknown
