title: Genomic analysis of a xylose operon and characterization of novel xylose isomerase and xylulokinase from Bacillus coagulans NL01.
abstract: OBJECTIVE
  To investigate the xylose operon and properties of xylose isomerase and xylulokinase in Bacillus coagulans that can effectively ferment xylose to lactic acid.
  
  
  RESULTS
  The xylose operon is widely present in B. coagulans. It is composed of four putative ORFs. Novel xylA and xylB from B. coagulans NL01 were cloned and expressed in Escherichia coli. Sequence of xylose isomerase was more conserved than that of xylulokinase. Both the enzymes exhibited maximum activities at pH 7-8 but with a high temperature maximum of 80-85 °C, divalent metal ion was prerequisite for their activation. Xylose isomerase and xylulokinase were most effectively activated by Ni(2+) and Co(2+), respectively.
  
  
  CONCLUSIONS
  Genomic analysis of xylose operon has contributed to understanding xylose metabolism in B. coagulans and the novel xylose isomerase and xylulokinase might provide new alternatives for metabolic engineering of other strains to improve their fermentation performance on xylose.
authors.affiliation: College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China.|Jiangsu Key Lab of Biomass-Based Green Fuels and Chemicals, Nanjing, 210037, People's Republic of China.
authors.forename: Zhaojuan
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China.
authors.forename: Xi
authors.initials: X
authors.lastname: Lin
authors.affiliation: College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China.
authors.forename: Ting
authors.initials: T
authors.lastname: Jiang
authors.affiliation: College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Ye
authors.affiliation: College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China. hgouyj@njfu.edu.cn.|Key Laboratory of Forest Genetics and Biotechnology of the Ministry of Education, Nanjing, 210037, People's Republic of China. hgouyj@njfu.edu.cn.
authors.forename: Jia
authors.initials: J
authors.lastname: Ouyang
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000235:genetics / Q000378:metabolism*; D000070000:Bacillus coagulans / Q000201:enzymology*; D009876:Operon / Q000235:genetics*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D014994:Xylose / Q000235:genetics*
chemical_list: D014994:Xylose; D017853:Phosphotransferases (Alcohol Group Acceptor); C032700:xylulokinase; D019747:Aldose-Ketose Isomerases; C023298:xylose isomerase
keywords: Bacillus coagulans; Lactic acid; Xylose isomerase; Xylose operon; Xylulokinase