Protein Production Through Microbial Conversion of Rice Straw by Multi-Strain Fermentation

Area of Science:

• Biotechnology
• Microbial Fermentation
• Bioconversion

Background:

• Single-strain fermentation has limitations in providing a complete lignocellulosic enzyme system.
• Enzymatic hydrolysis of rice straw (RS) is crucial for nutrient enrichment.
• Enhancing true protein (TP) content in feedstuffs is a significant agricultural goal.

Purpose of the Study:

• To screen microbial strains with high rice straw (RS) hydrolyzing and true protein (TP) enriching capabilities.
• To optimize solid-state fermentation (SSF) conditions for maximizing TP yield.
• To develop a scalable technique for feedstuff protein conversion.

Main Methods:

• Screening of microbial strains for enzymatic hydrolysis of rice straw.
• Optimization of solid-state fermentation (SSF) parameters: inoculum size, inoculation ratio, and inoculation time.
• Utilizing inducers (Mn2+ and veratryl alcohol) for lignin peroxidase (LiP) activity.

Main Results:

• A mixed culture of Aspergillus niger 14-8, Candida utilis, and Phanerochaete chrysosporium demonstrated superior performance.
• Optimal conditions included a 10% total inoculum size, a 1:2 ratio of N. crassa 14-8 to P. chrysosporium, and delayed inoculation of N. crassa 14-8 by one day.
• Maximum TP yield reached 8.89%, representing a 123.37% increase.

Conclusions:

• Multi-strain mixed fermentation significantly enhances TP production from rice straw.
• Optimized SSF conditions and specific microbial consortia are key to efficient bioconversion.
• The developed technique shows promise for large-scale feedstuff protein production.