Thermo-alkali-stable lipase from a novel Aspergillus niger: statistical optimization, enzyme purification, immobilization and its application in biodiesel production

Prep Biochem Biotechnol. 2021;51(3):225-240. doi: 10.1080/10826068.2020.1805759. Epub 2020 Aug 18.


The influences of nutritional components affecting lipase production from the new Aspergillus niger using wheat bran as substrate were studied by employing Plackett-Burman and central composite statistical designs. Out of the 11 medium components tested, sucrose, KH2PO4 and MgSO4 at final concentrations of 3.0, 1.0 and 0.5 g/L, respectively, were reported to contribute positively to enzyme production (20.09 ± 0.98 U/g ds). The enzyme was purified through ammonium sulfate precipitation followed by Sephadex G-100 gel filtration. Molecular mass of the purified lipase was 57 kDa as evident on SDS-PAGE. Different methods of immobilization were studied and the highest immobilization yield of 81.7 ± 2.18% was reported with agarose (2%) and the optimum temperature was raised from 45 to 50 °C. Immobilized lipase could retain 80% of its original activity at 60 °C after 1 hr of incubation, and was stable at pH values between neutral and alkaline pH. Lipase-catalyzed transesterification process of fungal oil resulted in a fatty acid methyl ester yield consisting of a high percentage of polyunsaturated fatty acids (83.6%), making it appropriate to be used as winter-grade biodiesel. The operational stability studies revealed that the immobilized lipase could keep 70% of its total activity after 5 cycles of the transesterification process.

Keywords: Aspergillus niger EM 2019; biodiesel production; experimental design; extracellular lipase; immobilization; solid-state fermentation.

MeSH terms

  • Alkalies
  • Aspergillus niger / enzymology*
  • Biofuels*
  • Biotechnology / methods
  • Catalysis
  • Chromatography, Gas
  • Enzymes, Immobilized / chemistry
  • Esterification
  • Esters / chemistry
  • Fatty Acids / chemistry
  • Fatty Acids, Unsaturated / chemistry
  • Hydrogen-Ion Concentration
  • Hydrolysis
  • Lipase / chemistry*
  • Molecular Weight
  • Phylogeny
  • Solvents / chemistry
  • Substrate Specificity
  • Temperature
  • Viscosity


  • Alkalies
  • Biofuels
  • Enzymes, Immobilized
  • Esters
  • Fatty Acids
  • Fatty Acids, Unsaturated
  • Solvents
  • Lipase