Evaluation of Bacterial Isolates and Their Polyhydroxylalkanoate (PHA) Yields from Hypersaline Water Body of Lagos, Nigeria

Abstract

Water body is inevitable for its advantages of biodegradability and biocompatibility. Therefore, hypersaline water bacteria from Lagos, Nigeria were scrutinized for glucose induced PHA production at three locations of 6.35á´¼ N 3.28á´¼ E (St1); 6.35á´¼ N 3.40á´¼ E (St2); and 6.36á´¼ N 3.47á´¼ E (St3) and from three different depths of 0-7cm, 50m and 100m below water surface. Bacterial isolation and 16S rDNA molecular identification including their PHA potential and yields were carried out with standard microbiological methods. Identified bacterial isolates with their similarities are Achromobacter agilis strain E2B (74.18% similar), Acinetobacter calcoaceticus strainsJL11 (85.68% similar), nine (9) Alcaligenes faecalisstrains (85.34-97.58 % similarities) and Alcaligenes spp are three (3),  Azospirillum brasilense (95.27% similar);  thirteen (13) Bacillus spp (88.44%-100% similarities) but, three (3) B.anthracisstrains (95.19-98.28% similarities), and seven (7) B. cereusstrains (95.15%-96.51% similarities). While, Enterobacter cloacae strain IARI-SL-41 (90.37% similar), Falsochrobactrum ovis strain B1315 (93.38% similar), Lysinibacillus fusiformis strain 28XG99 (97.04% similar), two (2) Ochrobactrum spp. (83.45%-91.74% similarities), Providencia stuartii strain AR_0026 (94.34% similar), three (3) Pseudomonas aeruginosa strain (95.39%-97.16% similarities) and two (2) Pseudomonas spp., Streptococcus agalactiae strain Neha2 (95.32% similar), Vagococcus fluvialis strain AWW1 (90.38% similar). PHA producing potential for the bacterial isolates is 62.6% (n=190) while, the percentage of PHA producers from 2 % glucose induction is 31.1% (n=119). However, the maximum PHA yield of 1.2630±0.0170 gL^-1 from this research is obtained from Alcaligenesfaecalis strain N1-4. However, 7 (3.7%) bacteria from this study yields double and above (≥ 1.0 gL^-1) quantity when compared to the standard PHA (crotonic acid) when induced by 2% glucose. the results obtained from this research indicates the need for further work on investigating the best carbon source for Alcaligenesfaecalis strain N1-4 optimum yield because of the PHA beneficial and importance in the applications of medicine, engineering, agriculture, entertainment and other household utilities.