Enhanced Bioremediation of Degreasers Polluted Wetland Soil using Bacillus amyloliquefaciens and Pseudomonas putida

Abstract

This study aimed to evaluate the enhanced bioremediation of degreasers: Aquabreak and Teepol polluted wetland soil using Bacillus amyloliquefaciens and Pseudomonas putida. It employs laboratory-scale experimental designs, statistical data and interpretation. The wetland soil samples were collected from Oguruama at latitudes 4o4/45.8// N and longitude 6o57.20/4// E in Degema Local Government Area, Rivers State, Nigeria. The Pseudomonas and Bacillus species used in this study were isolated from the wetland soil and identified using standard biochemical and molecular methods; the 16S rRNA extraction, amplification and sequencing were done. The bioremediation experimental set-up was carried out with the two bacteria Bacillus amyloliquefaciens(BAC) and Pseudomonas putida (PSD), the two degreasers are Aquabreak (AQ) and Teepol (TP). The nine (9) experimental set-ups in this study were: control (CTL), Aquabreak Polluted Soil (AQPS), Teepol Polluted Soil (TPPS), AQPS + PSD, AQPS + BAC, TPPS + PSD, TPPS+BAC, TPPS+PSD+BAC, AQPS+PSD+BAC. The Bioremediation potential of the respective test organisms were monitored for 28 days. Total Hydrocarbon Content (THC) was monitored using the Spectrophotometer (SPECVIS-720). Percentage (%) bioremediation was also determined to ascertain the potential of the treatment agents, singly and in combination. Evaluation of enhanced bioremediation of degreasers using THC values revealed the amount of degreaser remediated and percentage (%) remediation. The Aquabreak setup from the initial contamination value of 1,535mgkg-1 decreased in this order: AQPS+BAC (1265mgkg-1, 82.41%) > AQPS+PSD+BAC (1245mgkg-1, 81.11%) > AQPS+PSD (1065mgkg-1, 69.38%) > AQPS (without test organism)(565mgkg-1, 38.81%). Changes in THC during bioremediation of the Teepol degreaser revealed that the amount of degreaser remediated and the percentage bioremediation from the initial contaminated value of 5,990mg/kg during the 28 days in decreasing order is; TPPS+PSD+BAC (4815mgkg-1,80.38%) >TPPS+BAC (3135mgkg-1, 53.17%) > TPPS+PSD (2165mgkg-1,36.14%) >TPPS(without test organism) (1935mgkg-1, 32.30%). It was observed that Bacillus amyloliquefaciens had more degradability potential than Pseudomonas putida on the degreasers. The Teepol degreaser was more biodegradable than the Aquabreak degreaser considering the percentage of the degreaser remediation. Hence, Bacillus amyloliquefaciens is a better option for degreaser bioremediation and Teepol degreaser is recommended for both industrial and domestic use.