ISOLATION, IDENTIFICATION AND SCREENING OF HALOPHILIC BACTERIA FOR POLYHYDROXYALKANOATE (PHA) IN HYPERSALINE LAGOS WATER BODY, NIGERIA

This study aims to identify bacteria associated with hypersaline water body in Lagos State, Nigeria, screen them for their potential to produce polyhydroxyalkanoates (PHA) and determine the physicochemical properties of the water. Enumeration, identification and testing for growth at 3% w/v NaCl were carried out using standard microbiological techniques. Screening for PHA production potential of the bacteria was carried out using Sudan Black B staining techniques. Physicochemical analysis of the water (at depths of 0-0.07m, 50m and 100m) was determined using the methods of Association of Official Analytical Chemists. The highest and lowest bacterial loads of 20.66 ? 0.47 Cfu/mL and 10.00 ? 0.82 Cfu/mL were obtained from depth 50m respectively. Eighteen (18) bacteria namely Micrococcus varians, M. luteus, Bacillus badius, B. macquariensis, B. megaterium, Corynebacterium kutsceri, Mycobacterium delbrueckii, Mycobacterium smegmatis, Staphylococcus aureus, Staphylococcus saprophyticus, Staphylococcus epidermidis, Lactobacillus delbrueckii, Klebsiella pneumoniae subsp. pneumoniae, Neisseria veillonella, Enterobacter intermedius, Enterobacter amnigenus, Serratia marcescens and Yersinia pestis were phenotypically identified from this study using Bergeys Manual of Systematic Bacteriology. The test for growth at 3% w/v NaCl revealed that Bacillus badius had the highest optical density (OD) (2.84) at 520nm, while Serratia mercescens had the lowest OD (2.61) at 520nm. The physicochemical parameters of the hypersaline water ranged from 0.17 to 37.4NTU, 37300 to 43500μS/cm and 10 to 130mg/mL for turbidity, conductivity and alkalinity respectively. The values obtained for Dissolved Oxygen, Chemical Oxygen Demand and Biochemical Oxygen Demand ranged from 4.08 to 4.42mg/L, 4.21 to 3699mg/L and 4.21 to 924.75mg/L respectively. Findings from this study revealed that 88.1% of the bacteria tested positive to PHA production and the presence of PHA producing bacteria has been established in the hypersaline water body of Lagos State, Nigeri