title: Fibrinolytic enzymes from a newly isolated marine bacterium Bacillus subtilis A26: characterization and statistical media optimization.
abstract: A fibrinolytic enzyme producing bacterium was isolated and identified as Bacillus subtilis A26 on the basis of the 16S rRNA gene sequence. The fibrin zymography analysis reveals the presence of at least three fibrinolytic enzymes. The crude enzyme exhibited maximal activity at 60 degrees C and pH 8.0. Medium composition and culture conditions for the enzyme production by B. subtilis A26 were optimized using two statistical methods. The Plackett-Burman statistical design was applied to find the key ingredients and conditions for the best yield of enzyme production. Five significant variables (hulled grain of wheat, casein peptone, NaCl, CaCl2, and initial pH) were selected for the optimization studies. The response surface methodological approach was used to determine the optimal concentrations and conditions. The optimized medium contained 40.0 g.L-1 hulled grain of wheat, 3.53 g.L-1 casein peptone, 4.0 g.L-1 CaCl2, 3.99 g.L-1 NaCl, 0.01 g.L-1 MgSO4, and 0.01 g.L-1 KH2PO4, pH 7.78. The medium optimization resulted in a 4.2-fold increased level of fibrinolytic production (269.36 U.mL-1) compared with that obtained with the initial medium (63.45 U.mL-1). A successful and significant improvement in the production of protease by the A26 strain was accomplished using inexpensive carbon substrate (hulled grain of wheat), allowing a significant reduction in the cost of medium constituents.
authors.affiliation: Laboratoire de Genie Enzymatique et de Microbiologie, Ecole Nationale d'Ingenieurs de Sfax., Tunisia.
authors.forename: Rym
authors.initials: R
authors.lastname: Agrebi
authors.forename: Anissa
authors.initials: A
authors.lastname: Haddar
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hajji
authors.forename: Fakher
authors.initials: F
authors.lastname: Frikha
authors.forename: Laila
authors.initials: L
authors.lastname: Manni
authors.forename: Kemel
authors.initials: K
authors.lastname: Jellouli
authors.forename: Moncef
authors.initials: M
authors.lastname: Nasri
mesh_terms: D001412:Bacillus subtilis / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000096:biosynthesis*; D003067:Coenzymes / Q000494:pharmacology; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005341:Fibrinolysin / Q000096:biosynthesis*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D003067:Coenzymes; D003470:Culture Media; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D005341:Fibrinolysin