Bioremediation study of pentachlorophenol (PCP) in soil matrix using PCP degrader isolated from PCP acclimated sludge

• Main Author: Tan, Reasmey
• Format: text
• Language: English
• Published: Animo Repository 2007
• Subjects: Bioremediation; Pentachlorophenol; Pentachlorophenol—Toxicology; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/3479; https://animorepository.dlsu.edu.ph/context/etd_masteral/article/10317/viewcontent/CDTG004231_P.pdf
• Institution: De La Salle University

Pentachlorophenol (PCP) is listed as a priority toxic pollutant because of its high toxicity and low biodegradability in soil matrix. PCP biodegradation in soil is slow due to insufficient number of PCP degrader and inhibition by toxic concentration of PCP. Inoculation with PCP degraders (i.e. bioaugmentation) may, in some cases, be the only way for microbial clean-up of soil contaminated sites (Miethling and Karlson, 1996). The first phase of this study involved the acclimation of PCP as this process allowed microbes to adapt with the new substrate PCP by increasing the PCP concentration stepwise. PCP degrader was then isolated and identified. Moreover, physiological characteristics of this PCP degrader were also investigated. The second phase concerned with bioremediation of PCP in soil with different treatments including bioaugmentation, natural attenuation and control. The soil pH, conductivity, temperature, moisture content, microbial growth, CO2 evolution, PCP and chloride concentration were then investigated. Results showed that the isolated PCP degrader derived from PCP acclimated sludge was Pseudomonas putida. It was characterized as round gramnegative bacteria, non-sporulating rod, 1.25-1.5μm length and 0.4-0.5μm width with growth rate and specific growth rate calculated to be 0.0204 min-1 and 0.1416 h-1, respectively. The ability of P. putida was tested in a batch culture with PCP as sole carbon source and energy and test results showed that P. putida can degrade different PCP concentrations. Bioaugmentation had a faster degradation time of 10 days compared to that of 15 days using natural attenuation method. The chloride concentrations were observed to be 11.36ppm and 10.1ppm, respectively. This study concluded that it is possible to isolate PCP degrader from PCP acclimated sludge. The inoculation of PCP degrader has the potential for microbial clean-up of soil contaminated sites.