1. UKM Learning and Research Repository
2. PHD Thesis / Tesis PHD
3. Faculty of Science and Technology / Fakulti Sains dan Teknologi

Title:	Effects of biosurfactant on phytoremediation of gasoline using Ludwigia octovalvis and Scirpus mucronatus
Authors:	Al-Mansoory Asia Fadhile Abdullah (P55909)
Supervisor:	Mushrifah Idris, Prof. Dato' Dr.
Keywords:	Phytoremediation.
Issue Date:	5-Jul-2015
Description:	Contamination due to petroleum hydrocarbons will be the main problem at the end of this decade. Gasoline-contaminated soil is a great threat to the environment, and is common in oil-producing and industrialized countries. Phytoremediation is natural and environment friendly, with lower cost and substantial potential use in removing soil contaminants. In the current study, phytoremediation was used to treat gasoline-contaminated soil by analyzing total petroleum hydrocarbons (TPH) using native terrestrial (Ludwigia octovalvis) and submerging plants (Scirpus mucronatus). Phytotoxicity test was carried out using the two native tropical plants to remove TPH, served as the potential indicator of gasoline contamination in contaminated soil. L. octovalvis survived in different gasoline concentrations of 1, 2, and 3 g/kg and S. mucronatus was able to survive in gasoline concentrations of 5, 10, and 30 g/kg. In 2 g/kg gasoline, L. octovalvis removed 79.8% TPH. S. mucronatus removed 82.05% TPH at 10 g/kg gasoline concentration. Simultaneously, microbe screening was carried out using 15 isolates for biosurfactant production and gasoline degradation. The isolates were screened for their ability to produce biosurfactants based on surface tension measurement (mN/m), emulsification index (E24%), and other test for cell-free broth after cultivation in mineral salt medium. Results of the screening method from the 15 isolates showed high gasoline degradation and biosurfactant production by Serratia marcescens, which enhanced the phytoremediation process. The highest degree of degradation at 90.5% TPH was observed after S. marcescens was added in the soil mixture exposed to a gasoline concentration of 2 g/kg at 72 d after it has been planted with L. octovalvis. With S. marcescens, S. mucronatus exhibited 87.5% TPH degradation in 10 g/kg gasoline-contaminated soil within the same period. Based on the phytotoxicity test, adding the bacteria S. marcescens has resulted in higher efficiency in TPH removal. Optimum conditions for biosurfactant production from S. marcescens were determined based on the mineral salt medium containing glycerol, which served as the best carbon source, and peptone with ammonium sulfate, which served as the nitrogen source, in pH 8 at 200 rpm grown at 30 °C for 5 d. Response surface methodology was employed to optimize three operating variables, namely, glycerol, peptone, and ammonium sulfate, in different concentrations and under the condition resulting in the production of glucose and glycerophospholipid as biosurfactant. To determine the effects of biosurfactant in phytoremediation, different forms of surfactants were added as the supernatant, biosurfactant, raw S. marcescens, and commercial surfactant (sodium dodecyl sulfate), during the phytoremediation process to enhance gasoline removal in contaminated soil. Findings indicate that the biosurfactant produced from S. marcescens is active in TPH removal up to 93.5% when applied with L. octovalvis plant compared with S. mucronatus, which has a TPH removal rate of 79.3%. The supernatant has the lowest percentage in the degradation of TPH in soil mixtures of the two plants L. octovalvis and S. mucronatus.,Ph.D
Pages:	324
Call Number:	TD192.75 .M346 2015
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.