title: Biodegradation of kraft lignin by a newly isolated anaerobic bacterial strain, Acetoanaerobium sp. WJDL-Y2.
abstract: An anaerobic kraft lignin (KL)-degrading bacterial strain was isolated from sludge of a pulp and paper mill. It was characterized as Acetoanaerobium sp. WJDL-Y2 by 16S rRNA gene sequencing. The maximum KL degradation capability of strain Y2 was determined to be 24·9% on a COD basis under an optimal condition with temperature of 31·5°C, initial pH of 6·8 and KL to nitrogen (as NH4 Cl) ratio of 6·5 by mass. Growth kinetic studies showed that the KL tolerance of strain Y2 was relatively high (Ki  = 8120·45 mg l(-1) ). Analysing KL degradation products by GC-MS revealed the formation of low-molecular-weight aromatic compounds (LMWACs), including benzene-propanoic acid, syringic acid and ferulic acid. This indicates that strain Y2 can oxidize lignin structure's p-hydroxyphenyl (H) units, guaiacyl (G) units and syringyl (S). In addition, the inoculated sample also contained low-molecular acid compounds, such as hexanoic acid, adipic acid and 2-hydroxybutyric acid, further validating strain Y2's ability to degrade KL.
  
  
  CONCLUSIONS
  Kraft lignin containing effluents discharged from pulp and paper industries causes serious environmental pollution in developing countries. Due to the immense environmental adaptability and biochemical versatility, bacterial ligninolytic potential deserve to be studied for application in effluent treatment of pulp and paper industry. In this study, an anaerobic lignin-degrading bacterium, Acetoanaerobium sp. WJDL-Y2 (accession no. KF176997),was isolated from the sludge of a pulp and paper mill. Strain Y2 can play an important role in treating pulp and paper wastewater, as well as breaking down materials for biofuel and chemical production.
authors.affiliation: Department of Environmental Engineering, Xi'an Jiaotong University, Xi'an, China.
authors.forename: J
authors.initials: J
authors.lastname: Duan
authors.affiliation: Department of Environmental Engineering, Xi'an Jiaotong University, Xi'an, China.
authors.forename: X
authors.initials: X
authors.lastname: Huo
authors.affiliation: Department of Environmental Engineering, Xi'an Jiaotong University, Xi'an, China.
authors.forename: W J
authors.initials: WJ
authors.lastname: Du
authors.affiliation: Department of Environmental Engineering, Xi'an Jiaotong University, Xi'an, China.|State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science, Lanzhou, China.
authors.forename: J D
authors.initials: JD
authors.lastname: Liang
authors.affiliation: State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an, China.
authors.forename: D Q
authors.initials: DQ
authors.lastname: Wang
authors.affiliation: Department of Environmental Engineering, Xi'an Jiaotong University, Xi'an, China.
authors.forename: S C
authors.initials: SC
authors.lastname: Yang
mesh_terms: D000272:Adipates / Q000378:metabolism; D001673:Biodegradation, Environmental; D002208:Caproates / Q000378:metabolism; D003373:Coumaric Acids / Q000378:metabolism; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D006885:Hydroxybutyrates / Q000378:metabolism; D007220:Industrial Waste; D007700:Kinetics; D008031:Lignin / Q000378:metabolism*; D008969:Molecular Sequence Data; D010209:Paper; D010462:Peptostreptococcus / Q000302:isolation & purification* / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology*
chemical_list: D000272:Adipates; D002208:Caproates; D003373:Coumaric Acids; D006885:Hydroxybutyrates; D007220:Industrial Waste; D012336:RNA, Ribosomal, 16S; D012722:Sewage; C037652:hexanoic acid; D005707:Gallic Acid; C029900:adipic acid; C076151:Kraft lignin; D008031:Lignin; C004999:ferulic acid; C001945:syringic acid; C031570:2-hydroxybutyric acid
keywords: 16S rRNA gene sequencing; Acetoanaerobium sp. WJDL-Y2; GC-MS; growth kinetics; kraft lignin degradation; response surface methodology