Pectinase production by solid fermentation from Aspergillus niger by a new prescription experiment

Area of Science:

• Biotechnology and Industrial Microbiology
• Agricultural Science
• Animal Nutrition

Background:

• Peashrub (Caragana) is a dominant vegetation on the Ordos Plateau, suitable for fodder production.
• Optimizing culture conditions, particularly the substrate, is crucial for producing pectinase complex from peashrub fodder.

Purpose of the Study:

• To develop an optimized solid substrate formulation for enhanced pectinase production by Aspergillus niger.
• To evaluate the efficacy of the produced pectinase complex in improving goat feed efficiency.

Main Methods:

• A uniform experimental design was employed to optimize solid substrate components (water, wheat bran, rice dextrose, ammonium sulfate, Tween 80).
• A two-stage temperature treatment (30°C for 30h, then 23°C for 42h) was applied during fermentation.
• Multivariate regression analysis and mathematical programming were used to develop a predictive model and determine optimal substrate ratios.

Main Results:

• A second-degree polynomial model accurately predicted pectinase activity (R²=97.7%).
• The optimal substrate formula for pectinase production by Aspergillus niger was determined as: rice dextrose 8%, wheat bran 24%, ammonium sulfate 6%, and water 61%.
• Tween 80 negatively impacted pectinase production; the optimized substrate yielded 36.3 IU/(gDM) of pectinase. Goats fed this pectinase showed an average daily weight gain increase of 0.47 kg over 25 days.

Conclusions:

• The developed substrate formula significantly enhances pectinase production via solid-state fermentation.
• Pectinase supplementation shows promise for improving livestock nutrition, particularly for goats fed peashrub fodder.
• This approach offers a sustainable feeding strategy for arid and semi-arid pasture development.