Halotolerance of Heterotrophic Bacteria Isolated from Tropical Coastal Waters

Abstract

To initiate an understanding of the halotolerance of indigenous coastal water bacteria, the salt tolerance of a total of one hundred and seventy (170) surface water heterotrophic bacteria isolated from three (Badagry Creek, Ologe Lagoon and Lagos Lagoon) coastal waters in Lagos, Nigeria was evaluated. All isolates proliferated at NaCl concentrations of 0 to 4%, however, as the concentration of salt increased, the percentage of organisms able to grow decreased. At 15% salt concentration, only 10.7, 16.7 and 6.1% of the isolates from Badagry Creek, Ologe Lagoon and Lagos Lagoon respectively grew. Majority (51%) of the isolates grew at salt concentrations of 0 to 8% and were classified as moderately halotolerant, 35% were highly halotolerant growing beyond 8% (10 to 15%) salt concentrations, while 14% which grew between 0 and 4% were grouped as slightly halotolerant. The highest number of highly halotolerant bacteria was isolated from surface water with salinity 0.01 to 0.1