title: Microcalorimetric investigation of the effect of non-ionic surfactant on biodegradation of pyrene by PAH-degrading bacteria Burkholderia cepacia.
abstract: Polycyclic aromatic hydrocarbons (PAHs) are widespread in various ecosystems and are pollutants of great concern due to their potential toxicity, mutagenecity and carcinogenicity. Surfactant has become a hot topic for its wide application in the bioremediation of PAHs. The aim of this work is to explore a microcalorimetric method to determine the toxic effect of pyrene on Bacillus subtilis (B. subtilis) and the PAH-degrading bacteria Burkholderia cepacia (B. cepacia) and to evaluate the effect of Tween 80 on biodegradation of pyrene. Power-time curves were studied and calorimetric parameters including the growth rate constant (k), half inhibitory concentration (IC₅₀), and total thermal effect (Q(T)) were determined. B. subtilis, B. cepacia and B. cepacia with Tween 80 were completely inhibited when the concentration of pyrene were 200, 800 and 1600 µg mL⁻¹, respectively. B. cepacia shows better tolerance to pyrene than B. subtilis. Tween 80 significantly improves the biodegradation of pyrene by increasing the bioavailability of pyrene. In addition, the expression of catechol 2,3-dioxygenase (C23O) in B. cepacia is responsible for the degradation of pyrene and plays an important role in improving the biodegradation of pyrene. Moreover, the activity of C23O increases with the application of Tween 80. The enhanced bioavailability and biodegradation of pyrene by Tween 80 shows the potential use of Tween 80 in the PAHs bioremediation.
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology and Sino-Hungarian Joint Laboratory of Environmental Science and Health, School of Environmental Studies, China University of Geosciences, Wuhan 430074, PR China.
authors.forename: Ke
authors.initials: K
authors.lastname: Chen
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhu
authors.forename: Yiguang
authors.initials: Y
authors.lastname: Qian
authors.forename: Ying
authors.initials: Y
authors.lastname: Song
authors.forename: Jun
authors.initials: J
authors.lastname: Yao
authors.forename: Martin M F
authors.initials: MM
authors.lastname: Choi
mesh_terms: D001412:Bacillus subtilis / Q000187:drug effects; D001673:Biodegradation, Environmental; D016956:Burkholderia cepacia / Q000187:drug effects* / Q000378:metabolism; D002151:Calorimetry; D050557:Catechol 2,3-Dioxygenase / Q000378:metabolism; D004785:Environmental Pollutants / Q000737:chemistry* / Q000633:toxicity; D011136:Polysorbates / Q000494:pharmacology*; D011721:Pyrenes / Q000737:chemistry* / Q000633:toxicity; D013501:Surface-Active Agents / Q000494:pharmacology*
chemical_list: D004785:Environmental Pollutants; D011136:Polysorbates; D011721:Pyrenes; D013501:Surface-Active Agents; C030984:pyrene; D050557:Catechol 2,3-Dioxygenase
keywords: Biodegradation; Burkholderia cepacia; Microcalorimetry; Non-ionic surfactant; Pyrene