Proteolytic Enzyme Treatment for Biogas Substrate Degradation
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Solution Overview
Problem
Biogas production in biogas plants using renewable primary products like corn silage and grass silage is hindered by slow and incomplete degradation of fiber-rich substrates due to suboptimal nitrogen content and limited proteolytic activity of microbiota, leading to reduced biogas yields and increased viscosity.
Innovation Solution
The use of a method involving the treatment of substrates with proteolytic enzymes, specifically acid-stable serine proteases having at least 90% amino acid identity to certain polypeptides, in combination with carbohydrases such as amylases and NSP-degrading enzymes, to enhance biogas yield and degradation rate by liberating starch and proteins, thereby increasing nitrogen availability for microbial metabolism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carbohydrase preparations are used to degrade fiber-rich substrates, then biogas yield is improved, but degradation rate remains slow and incomplete
Solution Approach 1:
The patent combines proteolytic enzymes with carbohydrase preparations to create a synergistic enzyme system. The proteolytic enzymes break down proteins into amino acids and peptides, while carbohydrases degrade carbohydrates. This merging of enzyme functions accelerates overall substrate degradation and improves biogas yield more effectively than carbohydrases alone.
Solution Approach 2:
The invention uses composite enzyme preparations containing multiple types of enzymes (proteolytic enzymes and carbohydrases) working together. This composite approach addresses the limitations of single-enzyme systems by providing comprehensive degradation of both protein and carbohydrate components of fiber-rich substrates, thereby improving both degradation rate and biogas yield.
2Productivity
If nitrogen content is increased to improve microbial performance, then biogas production is enhanced, but substrate cost increases
Solution Approach 1:
The proteolytic enzymes in the preparation enable microorganisms to access and utilize nitrogen bound in protein forms within the substrate. This self-service mechanism allows the microbial community to liberate and use nitrogen internally from the substrate itself, reducing the need for external nitrogen supplementation while maintaining high biogas production.
Solution Approach 2:
The invention changes the bioavailability parameter of nitrogen by using proteolytic enzymes to convert bound nitrogen in proteins into free amino acids and peptides. This parameter change makes nitrogen more accessible to microorganisms, improving microbial performance and biogas production without requiring increased total nitrogen input.
3Productivity
If fiber-rich substrates are used to increase renewable energy production, then biogas yield potential is improved, but viscosity increases and degradation becomes incomplete
Solution Approach 1:
The enzyme preparation is added before the anaerobic digestion process to perform preliminary degradation of fiber-rich substrates. The proteolytic and carbohydratic enzymes pre-treat the substrate by breaking down complex proteins and carbohydrates, reducing viscosity and making the substrate more accessible to microbial degradation during the main digestion process, thereby improving complete degradation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly boosts biogas production by increasing the amount and rate of biogas produced, as evidenced by increased gas yields and faster degradation of substrates like corn silage and grass silage, addressing the limitations of existing carbohydrase preparations.
Implementation Method 1
treating the substrate with an efficient amount of one or more proteolytic enzymes alone or in combination with at least one carbohydrase
Implementation Method 2
the application of carbohydrate-degrading enzyme preparations (carbohydrases) has been shown to be beneficial for the break-down of cellulose or hemicellulose in plant material to simple sugars
Implementation Method 3
Biogas is produced by anaerobic microbiological degradation of liquid manure, energy plants (maize, grain), agricultural by-products or organic waste
Data Source
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AI summary
The invention relates to the use of at least one bacterial amylase and/or bacterial or fungal cellulase in combination with one or more protease(s) in substrates for anaerobic digestion processes for biogas production for improving degradation of maize, maize silages and/or other biogas substrates, in particular for improving gas yield, velocity and substrate conversion rate.