Response surface methodology for optimal immobilization of Aspergillus niger ATCC 1015 lipase by adsorption method

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 bran-physic 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.

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Optimization of Sodium Hydroxide Pretreatment and Enzymatic Hydrolysis of Wheat Straw Powder by Cellulases and Xylanases From Aspergillus Niger HQ-1 Using Response Surface Methodology

10.21203/rs.3.rs-374151/v1 ◽

2021 ◽

Author(s):

Hui Zhang ◽

Junhui Wu

Keyword(s):

Response Surface Methodology ◽

Enzymatic Hydrolysis ◽

Aspergillus Niger ◽

Sodium Hydroxide ◽

Wheat Straw ◽

Response Surface ◽

Sodium Hydroxide Solution ◽

Solid Loading ◽

Enzyme Loading ◽

Hydrolysis Of

Abstract To maximize fermentable sugars production, response surface methodology (RSM) was adopted to optimize pretreatment and enzymatic hydrolysis of wheat straw powder (WSP) using the crude cellulases preparation containing xylanases from Aspergillus niger HQ-1. Factors of pretreatment including sodium hydroxide concentration, pretreatment time and temperature were found to have significant effects on sugars production. Results indicated that WSP with particle size 0.3 mm should be pretreated using 1.8% (w/v) sodium hydroxide solution with 25.0% (w/v) of solid loading at 94.0°C for 46.0 min and the optimized pretreatment conditions could result in 90.9% of cellulose recovery, 54.6% of hemicellulose recovery and 72.7% of lignin removal, respectively. Furthermore, variables of enzymatic hydrolysis including enzyme loading, biomass loading and reaction time were proved to have significant effects on sugars yields. After hydrolysis at 50°C for 44.8 h with 7.1% (w/v) of biomass loading, 8.1 FPU/g of enzyme loading and 0.2% (w/v) of Tween-80, maximum yields of reducing sugar (632.92 mg/g) and xylose (149.83 mg/g) could be obtained, respectively. In addition, holocellulose and hemicellulose conversion were 81.6% and 80.0%, respectively. To the best of our knowledge, this is the first report about systematic optimization of sodium hydroxide pretreatment and enzymatic hydrolysis of WSP using RSM.

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