title: Lipolytic potential of Aspergillus japonicus LAB01: production, partial purification, and characterisation of an extracellular lipase.
abstract: Lipolytic potential of Aspergillus japonicus LAB01 was investigated by describing the catalytic properties and stability of a secreted extracellular lipase. Enzyme production was considered high under room temperature after 4 days using sunflower oil and a combination of casein with sodium nitrate. Lipase was partially purified by 3.9-fold, resulting in a 44.2% yield using ammonium sulphate precipitation (60%) quantified with Superose 12 HR gel filtration chromatography. The activity of the enzyme was maximised at pH 8.5, and the enzyme demonstrated stability under alkaline conditions. The optimum temperature was found to be 45°C, and the enzyme was stable for up to 100 minutes, with more than 80% of initial activity remaining after incubation at this temperature. Partially purified enzyme showed reasonable stability with triton X-100 and was activated in the presence of organic solvents (toluene, hexane, and methanol). Among the tested ions, only Cu(2+), Ni(2+), and Al(3+) showed inhibitory effects. Substrate specificity of the lipase was higher for C14 among various p-nitrophenyl esters assayed. The KM and V max values of the purified enzyme for p-nitrophenyl palmitate were 0.13 mM and 12.58 umol/(L·min), respectively. These features render a novel biocatalyst for industrial applications.
authors.affiliation: Cell Signaling, Nanobiotechnology and Enzymology Laboratory, Federal University of Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Lívia Tereza Andrade
authors.initials: LT
authors.lastname: Souza
authors.affiliation: Cell Signaling, Nanobiotechnology and Enzymology Laboratory, Federal University of Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Jamil S
authors.initials: JS
authors.lastname: Oliveira
authors.affiliation: Laboratory of Applied Microbiology, Federal University of Minas Gerais 31270-901, Belo Horizonte, MG, Brazil.
authors.forename: Vera L
authors.initials: VL
authors.lastname: dos Santos
authors.affiliation: Cell Signaling, Nanobiotechnology and Enzymology Laboratory, Federal University of Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Wiliam C B
authors.initials: WC
authors.lastname: Regis
authors.affiliation: Cell Signaling, Nanobiotechnology and Enzymology Laboratory, Federal University of Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Santoro
authors.affiliation: Cell Signaling, Nanobiotechnology and Enzymology Laboratory, Federal University of Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Rodrigo R
authors.initials: RR
authors.lastname: Resende
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D004795:Enzyme Stability; D004952:Esters / Q000737:chemistry; D006368:Helianthus / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000737:chemistry / Q000302:isolation & purification*; D008066:Lipolysis; D010938:Plant Oils / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004952:Esters; D010938:Plant Oils; D012997:Solvents; D008049:Lipase