title: Effect of rhamnolipid solubilization on hexadecane bioavailability: enhancement or reduction?
abstract: In this study, liquid culture systems containing rhamnolipid-solubilized, separate-phase, and multi-state hexadecane as the carbon source were employed for examining the effect of rhamnolipid solubilization on the bioavailability of hexadecane. Experimental results showed that the uptake of rhamnolipid-solubilized hexadecane by Pseudomonas aeruginosa ATCC 9027, a rhamnolipid producing strain, was enhanced compared to the uptake of mass hexadecane as a separate phase, indicating rhamnolipid solubilization increased the bioavailability of hexadecane for this bacterium. For Pseudomonas putida CICC 20575 which does not produce but degrade rhamnolipid, the uptake of either rhamnolipid-solubilized hexadecane or multi-state hexadecane was inhibited. The reduction of bioavailability was assumed to be the consequence of the blocking effect caused by the partition of rhamnolipid molecules at the hexadecane-water interface. The results show that how rhamnolipid solubilization changes the bioavailability of hexadecane depends on the bacterial compatibility to rhamnolipid. The study adds insight into the knowledge of biosurfactant-associated bioavailability of hydrophobic organic compounds (HOCs), and is of importance for application of biosurfactants in bioremediation of HOCs.
authors: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors: Yang
authors: Y
authors: Liu
authors: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China. Electronic address: zgming@hnu.edu.cn.
authors: Guangming
authors: G
authors: Zeng
authors: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China; State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, Hubei 430072, China. Electronic address: zhonghua@hnu.edu.cn.
authors: Hua
authors: H
authors: Zhong
authors: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors: Zhiquan
authors: Z
authors: Wang
authors: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors: Zhifeng
authors: Z
authors: Liu
authors: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors: Min
authors: M
authors: Cheng
authors: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors: Guansheng
authors: G
authors: Liu
authors: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors: Xin
authors: X
authors: Yang
authors: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors: Shaoheng
authors: S
authors: Liu
mesh_terms: D000473:Alkanes / Q000737:chemistry / Q000493:pharmacokinetics*; D001682:Biological Availability; D006017:Glycolipids / Q000737:chemistry*; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D016958:Pseudomonas putida / Q000378:metabolism*; D012995:Solubility
chemical_list: D000473:Alkanes; D006017:Glycolipids; C418382:rhamnolipid; C007932:n-hexadecane
keywords: Bioavailability; Biosurfactant; Hydrocarbons; Rhamnolipid; Solubilization