DIVERSITY OF BACTERIA COMMUNITY STRUCTURE DURING DETOXIFICATION PROCESS OF HERBICIDE/DIOXIN CONTAMINATED SOIL AT FIELD SMALL SCALE

  • Nguyễn Bá Hữu

Abstract

Bioremediation technology is widely used in detoxification treatment of chlorinated organic contaminants due to its cost effectivity and environmental safety. This technology has been applied in detoxification at several different scales ofherbicide/dioxin contaminated soil in US former military base at Danang airport. The GC-MS analytical results of residue of dioxin concentration in biotreatment soils showed the significant reduction of the toxicants in the bioremediation at scale 0.5 m3 soil. In previous studies, the change of microbial community structure was usually performed by cultural method. Therefore, that does not reflect the exact phenomena of microbes in different biotreatments. In this study, analysis single strand conformation polymorphism (SSCP) of a part of 16S rRNA gene was used to study the change of bacterial community structure at 0.5 m3 biotreatment scale. There was no significant change on bacterial community structure between the 3 different sampling times in control experiment 0,5DN5. However, the change of bacterial community structure in different sampling times and in different biotreatment experiments was found. Biotreatment experiments also showed more diverse than in the control experiment 0,5DN5. The supply of carbon source derived from sugar-cane refinery to 0,5DN4 biotreatment experiment might cause the decrease of growth in bacterial communities. The suitable supply of carbon sources lead to the increase of bacterial diversity in two other biotreatments O,5DN2 and O,5DN3 in comparison to the rest. The DNA clones excised from SSCP gel belonged to 7 classes of a, J3 and y-Proteobacteria, Clostridia, Actinobacteria, Bacteroides and Bacilli. Some clones showed a close relationship to anaerobic bacteria such as Clostridia, Tissierella, facultative anaerobic bacteria Lactobacillus and Dysgonomonas mossii. The genera Escherichia and Citrobacter were also found in biotreatment experiments. Bacteria Pseudomonades including Pseudomonas stut=eri and other representative of genera Burkholderia, Alcaligenes, Kersteria, Delftia in Betaproteobacteria were also dominant in all of biotreatments. Many bacteria of these genera are able to degrade 2,4-D, 2,4,5-T and dioxin. The results in this study provide fundamental bases for scientists and technologists to enhance the rate of detoxification ofherbicide/dioxin as well as other toxic chemical contaminated soil in Vietnam.

Tác giả

Nguyễn Bá Hữu
điểm /   đánh giá
Published
2011-11-29
Section
Articles