title: Simultaneous lactic acidification and coagulation by using recombinant Lactococcus lactis strain.
abstract: OBJECTIVE
  This study was an attempt to create a novel milk clotting procedure using a recombinant bacterium capable of milk coagulation.
  
  
  RESULTS
  The Rhizomucor pusillus proteinase (RPP) gene was sub-cloned into a pALF expression vector. The recombinant pALF-RPP vector was then electro-transferred into Lactococcus lactis. Finally, the milk coagulation ability of recombinant L. lactis carrying a RPP gene was evaluated. Nucleotide sequencing of DNA insertion from the clone revealed that the RPP activity corresponded to an open reading frame consisting of 1218 bp coding for a 43·45 kDa RPP protein. The RPP protein assay results indicated that the highest RPP enzyme expression with 870 Soxhlet units (SU) per ml and 7914 SU/OD were obtained for cultures which were incubated at pH 5·5 and 30°C. Interestingly, milk coagulation was observed after 205 min of inoculating milk with recombinant L. lactis carrying the RPP gene.
  
  
  CONCLUSIONS
  The recombinant L. lactis carrying RPP gene has the ability to function as a starter culture for acidifying and subsequently coagulating milk by producing RPP as a milk coagulant agent.
  
  
  CONCLUSIONS
  Creating a recombinant starter culture bacterium that is able to coagulate milk. It is significant because the recombinant L. lactis has the ability to work as a starter culture and milk coagulation agent.
authors.affiliation: Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: M
authors.initials: M
authors.lastname: Raftari
authors.affiliation: Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran.|Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: S
authors.initials: S
authors.lastname: Ghafourian
authors.affiliation: Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: F
authors.initials: F
authors.lastname: Abu Bakar
mesh_terms: D000818:Animals; D019344:Lactic Acid / Q000378:metabolism; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism; D008892:Milk; D010447:Peptide Hydrolases / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D020103:Rhizomucor / Q000201:enzymology / Q000235:genetics
chemical_list: D011994:Recombinant Proteins; D019344:Lactic Acid; D010447:Peptide Hydrolases
keywords: 
  Lactococcus lactis
  ; cloning; coagulation; expression; proteinase