Identification and characterization of gram-negative bacteria from sponges

Abstract

To date, bacteria associated with sponges are still under investigation. This study was conducted to know the variability of microbial consortia associated with marine sponges and how far the association involves. The aims of this study are to isolate, identify and characterize the bacteria associate with marine sponges. Bacterial cultures were characterized by Gram-staining, macromorphology, micromorphology and biochemical tests. The result obtained from morphological observation and Gram­ staining shows that all the bacteria are Gram-negative with cocci and rod shape. Most of the bacteria shows positive reaction in both catalase and oxidase tests respectively. Other than that, only 21 % of the isolated bacteria showed positive result for starch hydrolysis test. All of the bacteria were not produce hydrogen sulfide and indole and most of the bacterial are non-motile in Sulfur, Indole and Motility (SIM) test. Only 3% of isolated bacteria produced bubble in Triple Sugar Ion (TSI) test and 40% are non-fermenter bacteria. In Voges-Proskauer test, only 2% of isolated bacteria showed negative result. The results of this study indicated that Pseudomonas sp. and Neisseria sp. are the dominant bacteria associated with sponges followed by Aeromonas sp. Aeromonas sp. can be classified until the species level which are Aeromonas veronii and Aeromonas salmonicida. Result of this study might be useful for data compilation for future studies on diversity of marine bacteria associated with sponges.