title: Molecular Mechanisms of Enhanced Bacterial Growth on Hexadecane with Red Clay.
abstract: Red clay was previously used to enhance bioremediation of diesel-contaminated soil. It was speculated that the enhanced degradation of diesel was due to increased bacterial growth. In this study, we selected Acinetobacter oleivorans DR1, a soil-borne degrader of diesel and alkanes, as a model bacterium and performed transcriptional analysis using RNA sequencing to investigate the cellular response during hexadecane utilization and the mechanism by which red clay promotes hexadecane degradation. We confirmed that red clay promotes the growth of A. oleivorans DR1 on hexadecane, a major component of diesel, as a sole carbon source. Addition of red clay to hexadecane-utilizing DR1 cells highly upregulated β-oxidation, while genes related to alkane oxidation were highly expressed with and without red clay. Red clay also upregulated genes related to oxidative stress defense, such as superoxide dismutase, catalase, and glutaredoxin genes, suggesting that red clay supports the response of DR1 cells to oxidative stress generated during hexadecane utilization. Increased membrane fluidity in the presence of red clay was confirmed by fatty acid methyl ester analysis at different growth phases, suggesting that enhanced growth on hexadecane could be due to increased uptake of hexadecane coupled with upregulation of downstream metabolism and oxidative stress defense. The monitoring of the bacterial community in soil with red clay for a year revealed that red clay stabilized the community structure.
authors.affiliation: Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 136-713, Republic of Korea.
authors.forename: Jaejoon
authors.initials: J
authors.lastname: Jung
authors.affiliation: Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 136-713, Republic of Korea.
authors.forename: In-Ae
authors.initials: IA
authors.lastname: Jang
authors.affiliation: Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 136-713, Republic of Korea.
authors.forename: Sungeun
authors.initials: S
authors.lastname: Ahn
authors.affiliation: Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 136-713, Republic of Korea.
authors.forename: Bora
authors.initials: B
authors.lastname: Shin
authors.affiliation: Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 136-713, Republic of Korea.
authors.forename: Jisun
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 136-713, Republic of Korea.
authors.forename: Chulwoo
authors.initials: C
authors.lastname: Park
authors.affiliation: Department of Life Science, Dongguk University, Seoul, 100-715, Republic of Korea.
authors.forename: Seung Cheol
authors.initials: SC
authors.lastname: Jee
authors.affiliation: Department of Life Science, Dongguk University, Seoul, 100-715, Republic of Korea.
authors.forename: Jung-Suk
authors.initials: JS
authors.lastname: Sung
authors.affiliation: Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 136-713, Republic of Korea. wpark@korea.ac.kr.
authors.forename: Woojun
authors.initials: W
authors.lastname: Park
mesh_terms: D000150:Acinetobacter / Q000254:growth & development* / Q000378:metabolism; D000473:Alkanes / Q000378:metabolism*; D000538:Aluminum Silicates; D001673:Biodegradation, Environmental; D058448:Biota; D002244:Carbon / Q000378:metabolism; D000077215:Clay; D018384:Oxidative Stress; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017423:Sequence Analysis, RNA; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism
chemical_list: D000473:Alkanes; D000538:Aluminum Silicates; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D002244:Carbon; C007932:n-hexadecane; D000077215:Clay
keywords: Alkane; Bioremediation; Diesel; Red clay; Transcriptome