title: Pseudosolubilized n-alkanes analysis and optimization of biosurfactants production by Pseudomonas sp. DG17.
abstract: The pseudosolubilized medium-chain-length n-alkanes during biodegradation process, and optimization of medium composition and culture conditions for rhamnolipid production by Pseudomonas sp. DG17 using Plackett-Burman design and Box-Behnken design, were examined in this study. The results showed that pseudosolubilized concentration of C14 to C20 n-alkanes was higher than that of C24 to C26. After incubation for 120 h, pseudosolubilized C16H34 increased to 2.63 ± 0.21 mg. Meanwhile, biodegradation rates of n-alkanes decreased along with the increase of carbon chain length. Carbon-14 assay suggested that nonlabeled C14H30, C16H34, and C20H42 inhibited the biodegradation of (14)C n-octadecane, and Pseudomonas sp. DG17 utilized different alkanes simultaneously. Three significant variables (substrate concentration, salinity, and C/N) that could influence rhamnolipid production were screened by Plackett-Burman design. Results of Box-Behnken design suggested that rhamnolipid concentration could be achieved at 91.24 mg L(-1) (observed value) or 87.92 mg L(-1) (predicted value) with the optimal levels of concentration, salinity, and C/N of 400 mg L(-1), 1.5 %, and 45, respectively.
authors.affiliation: College of Water Sciences, Beijing Normal University, No. 19, XinJieKouWai St., HaiDian District, Beijing, 100875, People's Republic of China, huafei412@163.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Hua
authors.forename: Hong Qi
authors.initials: HQ
authors.lastname: Wang
authors.forename: Yi Cun
authors.initials: YC
authors.lastname: Zhao
authors.forename: Yan
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000473:Alkanes / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002250:Carbon Radioisotopes; D006017:Glycolipids / Q000378:metabolism*; D010578:Petroleum / Q000378:metabolism; D059392:Petroleum Pollution / Q000517:prevention & control; D011549:Pseudomonas / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism; D012995:Solubility; D013501:Surface-Active Agents / Q000378:metabolism*
chemical_list: D000473:Alkanes; D002250:Carbon Radioisotopes; D006017:Glycolipids; D010578:Petroleum; D012989:Soil Pollutants; D013501:Surface-Active Agents; C418382:rhamnolipid; C022883:octadecane