Isolation and Molecular Characterization of Acid Producing Bacteria from Selected Oilfield Environments within the Niger Delta

Abstract

Acid producing bacteria are considered an important group of corrosive bacteria that have economic importance to petroleum industry. In this research, acid producing bacteria were isolated from produced water sample collected at ten (10) oil field environments within the Niger Delta region. The multiple tube fermentation technique was used to isolate the bacteria while Phenol red dextrose broth was used as the microbiological medium for the isolation of the acid producing bacteria. Also total heterotrophic bacteria count (THBC) was determined under aerobic and anaerobic condition using the standard plate count technique and the boiling method used for the extraction of acid producing bacterial DNA after growing in Luria Bertani broth. The extracted bacterial DNA were purified and quantified before PCR amplification. The PCR amplicons were subjected to gel electrophoresis. The bacterial DNA bands were quantified using 1500bp ladder. The result obtained showed that some acid producing bacteria isolated could survive as facultative microorganisms belonging to genera such as Klebsiella, Pantoea, Escherichia, Providentia, Proteus, Shewanella, Myroides and Pseudomonas. There was growth in all samples under aerobic condition with a THBC ranging from 3.602x102Cfu/ml – 4.698x102Cfu/ml while the range was within 3.301x102Cfu/ml – 5.676x102Cfu/ml under anaerobic condition. For physicochemical parameters determined, temperature range for all samples was within 23.9ºC – 24.8ºC; pH was within 7.24 – 8.10; total dissolved solids was within 470 mg/ml – 16160 mg/ml and conductivity was within 1.885 µs/cm – 845.2 µs/cm.  The results also showed that acid producing bacteria grow mostly under aerobic condition unlike the sulphate reducing bacteria.