title: Pyrene biodegradation with layer-by-layer assembly bio-microcapsules.
abstract: Biotechnology is considered as a promising technology for the removal of polycyclic aromatic hydrocarbons from the environment. Free bacteria are often sensitive to some biotic and abiotic factors in the environment to the extent that their ability to effect biodegradation of organic pollutants, such as polycyclic aromatic hydrocarbons, is hampered. Consequently, it is imperative to carry out investigations into biological systems that will obviate or aid tolerance of bacteria to harsh environmental conditions. Chitosan/alginate bio-microcapsules produced using layer-by-layer (LBL) assembly method were tested for pyrene (PYR) biodegradation under harsh environmental conditions. Morphology observation indicated that the flake bio-microcapsules could be successfully prepared through LBL assembly method. Surface analysis showed that the bio-microcapsules had large fractions of mesopores. The results of the biodegradation experiments revealed that the 95% of 10mgL-1PYR could be removed by the bacteria encapsulated chitosan/alginate bio-microcapsules in 3 days, which was higher than that of the free bacteria (59%). Compared to the free cells, the bacteria encapsulated chitosan/alginate bio-microcapsules produced 1-6 times higher PYR biodegradation rates at a high initial PYR concentration (50mgL-1) and extremely low pH values (pH =3) or temperatures (10°C or 40°C), as well as high salt stress. The results indicated that bacteria in microcapsules treatment gained a much higher tolerance to environmental stress and LBL bio-microcapsule could be promising candidate for remediating the organic pollutants.
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou 510006, China; School of Environmental and Biological Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China.
authors.forename: Fucai
authors.initials: F
authors.lastname: Deng
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
authors.forename: Zhengfang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou 510006, China. Electronic address: cyanggz@scut.edu.cn.
authors.forename: Chen
authors.initials: C
authors.lastname: Yang
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
authors.forename: Chuling
authors.initials: C
authors.lastname: Guo
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
authors.forename: Guining
authors.initials: G
authors.lastname: Lu
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou 510006, China. Electronic address: chzdang@scut.edu.cn.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Dang
mesh_terms: D000464:Alginates / Q000494:pharmacology*; D001673:Biodegradation, Environmental; D002214:Capsules; D018914:Cells, Immobilized; D048271:Chitosan / Q000494:pharmacology*; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D008863:Microspheres; D009170:Nontuberculous Mycobacteria / Q000378:metabolism*; D011721:Pyrenes; D012989:Soil Pollutants; D013696:Temperature
chemical_list: D000464:Alginates; D002214:Capsules; D006603:Hexuronic Acids; D011721:Pyrenes; D012989:Soil Pollutants; D020723:Glucuronic Acid; D048271:Chitosan; C030984:pyrene
keywords: Bio-microcapsules; Biodegradation; Environmental stress; Environmental tolerance; Layer-by-layer assembly; Pyrene