title: Changes in bacterial diversity associated with bioremediation of used lubricating oil in tropical soils.
abstract: Used lubricating oil (ULO) is a widespread contaminant, particularly throughout tropical regions, and may be a candidate for bioremediation. However, little is known about the biodegradation potential or basic microbial ecology of ULO-contaminated soils. This study aims to determine the effects of used ULO on bacterial community structure and diversity. Using a combination of culture-based (agar plate counts) and molecular techniques (16S rRNA gene sequencing and DGGE), we investigated changes in soil bacterial communities from three different ULO-contaminated soils collected from motorcycle mechanical workshops (soil A, B, and C). We further explored the relationship between bacterial community structure, physiochemical soil parameters, and ULO composition in three ULO-contaminated soils. Results indicated that the three investigated soils had different community structures, which may be a result of the different ULO characteristics and physiochemical soil parameters of each site. Soil C had the highest ULO concentration and also the greatest diversity and richness of bacteria, which may be a result of higher nutrient retention, organic matter and cation exchange capacity, as well as freshness of oil compared to the other soils. In soils A and B, Proteobacteria (esp. Gammaproteobacteria) dominated the bacterial community, and in soil C, Actinobacteria and Firmicutes dominated. The genus Enterobacter, a member of the class Gammaproteobacteria, is known to include ULO-degraders, and this genus was the only one found in all three soils, suggesting that it could play a key role in the in situ degradation of ULO-contaminated tropical Thai soils. This study provides insights into our understanding of soil microbial richness, diversity, composition, and structure in tropical ULO-contaminated soils, and may be useful for the development of strategies to improve bioremediation.
authors.affiliation: Biotechnology for Bioresource Utilization Laboratory, Department of Industrial Biotechnology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, 90112, Thailand.
authors.forename: Naruemon
authors.initials: N
authors.lastname: Meeboon
authors.affiliation: Institute of Arctic Biology, University of Alaska Fairbanks, 902 N. Koyukuk Dr., Fairbanks, AK, 99775, USA.
authors.forename: Mary-Cathrine
authors.initials: MC
authors.lastname: Leewis
authors.affiliation: Marine Natural Products Research Unit, Department of Pharmacognosy and Pharmaceutical Botany, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hat Yai, 90112, Thailand.
authors.forename: Sireewan
authors.initials: S
authors.lastname: Kaewsuwan
authors.affiliation: Biotechnology for Bioresource Utilization Laboratory, Department of Industrial Biotechnology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, 90112, Thailand.
authors.forename: Suppasil
authors.initials: S
authors.lastname: Maneerat
authors.affiliation: Institute of Arctic Biology, University of Alaska Fairbanks, 902 N. Koyukuk Dr., Fairbanks, AK, 99775, USA. mbleigh@alaska.edu.
authors.forename: Mary Beth
authors.identifier: http://orcid.org/0000-0002-0414-9350
authors.initials: MB
authors.lastname: Leigh
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D044822:Biodiversity; D054327:Lubricants / Q000032:analysis / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*; D014329:Tropical Climate
chemical_list: D054327:Lubricants; D012336:RNA, Ribosomal, 16S; D012987:Soil; D012989:Soil Pollutants
keywords: Bacterial community; Illumina MiSeq; PCR–DGGE; Used lubricating oil