title: Disruption of the Zymomonas mobilis extracellular sucrase gene (sacC) improves levan production.
abstract: OBJECTIVE
  Disruption of the extracellular Zymomonas mobilis sucrase gene (sacC) to improve levan production.
  
  
  RESULTS
  A PCR-amplified tetracycline resistance cassette was inserted within the cloned sacC gene in pZS2811. The recombinant construct was transferred to Z. mobilis by electroporation. The Z. mobilis sacC gene, encoding an efficient extracellular sucrase, was inactivated. A sacC defective mutant of Z. mobilis, which resulted from homologous recombination, was selected and the sacC gene disruption was confirmed by PCR. Fermentation trials with this mutant were conducted, and levansucrase activity and levan production were measured. In sucrose medium, the sacC mutant strain produced threefold higher levansucrase (SacB) than the parent strain. This resulted in higher levels of levan production, whilst ethanol production was considerably decreased.
  
  
  CONCLUSIONS
  Zymomonas mobilis sacC gene encoding an extracellular sucrase was inactivated by gene disruption. This sacC mutant strain produced higher level of levan in sucrose medium because of the improved levansucrase (SacB) than the parent strain.
  
  
  CONCLUSIONS
  The Z. mobilis CT2, sacC mutant produces high level of levansucrase (SacB) and can be used for the production of levan.
authors.affiliation: Department of Microbial Technology, Centre for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai, India.
authors.forename: V
authors.initials: V
authors.lastname: Senthilkumar
authors.forename: N
authors.initials: N
authors.lastname: Rameshkumar
authors.forename: S J W
authors.initials: SJ
authors.lastname: Busby
authors.forename: P
authors.initials: P
authors.lastname: Gunasekaran
mesh_terms: D003470:Culture Media; D018274:Electroporation; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005630:Fructans / Q000096:biosynthesis*; D005798:Genes, Bacterial; D005947:Glucose / Q000378:metabolism; D006602:Hexosyltransferases / Q000096:biosynthesis; D016254:Mutagenesis, Insertional / Q000379:methods*; D013393:Sucrase / Q000235:genetics*; D013753:Tetracycline Resistance / Q000235:genetics; D017355:Zymomonas / Q000235:genetics* / Q000378:metabolism
chemical_list: D003470:Culture Media; D005630:Fructans; D000431:Ethanol; C072599:levan; D006602:Hexosyltransferases; C021513:levansucrase; D013393:Sucrase; D005947:Glucose