Biodegradation of bioemulsified heavy oil in mangrove soil

Abstract

When oil is released into coastal areas and estuaries, it adheres to the roots of trees and seedlings, causing their asphyxiation and death within a few days. To mitigate this problem, the restoration of mangrove soil contaminated with emulsified oil was evaluated through the application of bacterial surfactant produced by a strain of Azospirillum lipoferum and another surfactant produced from pine oil. Risophora mangle propagules were collected from a mangrove forest located in the community of El Bellote, Paraíso, Tabasco, Mexico and planted in artificial solonchak sandy soil. When the R. mangle plants were three months old, their soil was contaminated with emulsified oil. The heavy oil fraction content and number of measurements. Factor A: type of surfactant: bacterial or pine oil; Factor B: emulsified oil concentration: 0, 30000, 40000, 50000, 60000 or 70000 ppm. Each treatment was performed in triplicate. The results were highly significant (p<0.0001) for the main effects, i.e., the concentrations of emulsified oil and surfactant, and for the treatment‒time interaction. For the 30000 ppm petroleum concentration, the percentages of oil removed by the bacterial surfactant and the pine oil were 93.98% and 81.39%, respectively. All R. mangle plants survived the bacterial surfactant treatment, in contrast to the pine oil surfactant, which caused the death of all the plants at the end of the treatment.
colony-forming units were evaluated through bioassays. These variables were analyzed with
a completely random design with a 2 × 6 factorial arrangement and time-repeated