Bacterial Profile of Biofilm forming bacteria in BFAR-NFRDI prawn pond at Pacita Lala, Lanao del Norte

Marden M. Ocat and Buenaflor D. Jimenez
MSU-Iligan Institute of Technology

Twenty-four slide sets were randomly deployed in NFRDI prawn pond to investigate the different functional groups forming the biofilm. Three slide sets were retrieved every week, one set for indirect count using artificial media and two slide sets for direct count using epiflourescence microscope.
A total of 48 isolates were observed: 18 heterotrophs, ten Vibrio, four Pseudomonas, five sulfur reducers, seven nitrate reducers, two lactose fermentors and two nitrite reducers. The heterotrophs and Vibrio were present during the entire sampling period and dominated the bacterial growth in the first sampling. Sulfur reducers were only observed by the seventh week. Although the lactose fermentors are present during the entire sampling period, they were only observed in small number. Nitrate and nitrite reducers took turns in dominating each other from weeks 2 to 8.
For the direct count, five morphological types were observed: a) medium sized orange cells, b) medium sized black cells c) small sized black cells d) small sized orange cells and e) big sized orange cells. The number of cells colonizing the slides increased with the length of exposure weekly from 79 cells/mm2 in Wk 1, to 166cells/mm2in Wk 8. The number of morphological types also increases with age. The medium sized orange colonies first colonized the biofilm and are present during the entire sampling period. The second colonizers were the medium sized black cells followed by the small sized black colonies. The small sized orange cells were only able to colonize at Wk 5 and also dominated that culture period. The big orange colonies were the last to colonize appearing only on Wk 6. The small sized black cells appeared only on the third week but dominated Wk 4, Wk 6 and Wk 8.