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Lipase of Aspergillus niger ATCC 1015 was immobilized onto matrices of a structural fibrous network (SFN) of pawpaw (Carica papaya) wood and vegetable sponge (VS) of (Luffa aegyptiaca) by physical entrapment through solid‐state fermentation. SFN‐ and VS‐immobilized lipases were characterized in terms of their operational and storage stability. The immobilizates were cross‐linked with ethanolic formaldehyde (EF), formaldehyde (F) and glutaraldehyde (GA). Ninety percent enzymatic activity was retained with GA as a coupling agent after 11 consecutive uses of SFN‐immobilized lipase, and after five, six, and four reuse times with EF, F, and uncross‐linked lipase, respectively. They showed different enzymatic characteristics (incubation time and operational stability) from those of VS‐immobilized enzyme. A relative activity above 75% was still achieved for the sample stored at 4°C and 50% at 28°C until fourth week of storage for both SFN‐ and VS‐immobilized lipases. In relation to the free biomass of A. niger ATCC 1015 hyphal cells, the SFN‐immobilized biomass with peak lipase activity (24.5 Ug−1) at day three resulted in 45.3% decrease in lipase production, whereas VS‐immobilized biomass with peak activity of 45.3 Ug−1 at day four resulted in 21.4% increase. This study revealed the potential of GA cross‐linked SFN as an excellent immobilizing agent.

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Optimization of Vegetable Sponge (Luffa aegyptiaca) (VS) -immobilization conditions of Aspergillus niger ATCC 1015 lipase on Solid State Fermentation (SSF) was carried out using Response Surface Methodology (RSM). Four independent variables (temperature, pH, enzyme loading and enzyme stability) were optimized using Central Composite Design of RSM for lipase production in a solid rice branphysic nut cake medium. The optimal immobilization conditions obtained were 45 °C, pH 7.0, 2.5% (w/v) enzyme loading and 32.5% (v/v) enzyme stability (using glutaraldehyde as crosslinking agent) resulted into lipase activity of 98.6 Ug -1 . The result demonstrates the potential application of vegetable sponge under SSF system in immobilizing lipase, thus contributed to efficiency of the use of this biomatrix as an immobilizing agent. The statistical tools employed predicted the optimal conditions for the production of the immobilized lipase thus revealing the full potential of the support.