Isolation of a Aspergillus niger lipase from a solid culture medium with aqueous

N. IMELIO; A. MARINI; G. PICÓ; D. ROMANINI; B. FARRUGGIA

JOURNAL OF CHROMATOGRAPHY B

ELSEVIER

Lugar: Amsterdam; Año: 2011 vol. 879 p. 2135 - 2141

0378-4347

The aim of this work is to find the best conditions to isolate lipase from a solid culture medium of  Aspergillus niger NRRL3 strains using queous two-phase systems formed with polyethylene glycol and  potassium phosphate or polyethylene glycol and sodium citrate. We studied the partitioning of a commercial  lyophilizate from A. niger. Also, the lipase enzymatic activity was studied in all the phases of the  systems and the results indicate that citrate anion increases lipase activity. An analysis by fluorescence  spectroscopy of the interaction between lipase and the bottom and top phases of the systems shows that  the protein tryptophan-environments are modified by the presence of PEG and salts. Separation of the  enzyme from the rest of the proteins that make up the lyophilized was achieved with good yield and  separation factor by ATPS formed by PEG 1000/Pi at pH 7, PEG 2000/Ci at pH 5.2 and PEG 4000/Ci at pH  5.2. The above mentioned systems were used in order to isolate extracellular lipase from a strain of A.  niger in submerged culture and solid culture. The best system for solid culture, with high purification  factor (30.50), is the PEG 4000/Ci at pH 5.2. The enzyme was produced in a solid culture medium whose  production is simple and recovered in a phase poor in polymer, bottom phase. An additional advantage  is that the citrate produces less pollution than the phosphate. This methodology could be used as a first  step for the isolation of the extracellular lipase from A. niger.Aspergillus niger NRRL3 strains using queous two-phase systems formed with polyethylene glycol and  potassium phosphate or polyethylene glycol and sodium citrate. We studied the partitioning of a commercial  lyophilizate from A. niger. Also, the lipase enzymatic activity was studied in all the phases of the  systems and the results indicate that citrate anion increases lipase activity. An analysis by fluorescence  spectroscopy of the interaction between lipase and the bottom and top phases of the systems shows that  the protein tryptophan-environments are modified by the presence of PEG and salts. Separation of the  enzyme from the rest of the proteins that make up the lyophilized was achieved with good yield and  separation factor by ATPS formed by PEG 1000/Pi at pH 7, PEG 2000/Ci at pH 5.2 and PEG 4000/Ci at pH  5.2. The above mentioned systems were used in order to isolate extracellular lipase from a strain of A.  niger in submerged culture and solid culture. The best system for solid culture, with high purification  factor (30.50), is the PEG 4000/Ci at pH 5.2. The enzyme was produced in a solid culture medium whose  production is simple and recovered in a phase poor in polymer, bottom phase. An additional advantage  is that the citrate produces less pollution than the phosphate. This methodology could be used as a first  step for the isolation of the extracellular lipase from A. niger.