Enzymatic VFA Control in Papermaking Starch Water Loops
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Solution Overview
Problem
Papermaking processes face issues with microbial starch degradation leading to volatile fatty acid (VFA) production, which causes unpleasant odors and product contamination due to the growth of facultative anaerobic microorganisms in closed water systems, exacerbated by catalytic metal ions and inefficient biocides.
Innovation Solution
A non-biocidal enzymatic VFA control agent, comprising enzymes like oxidases, proteases, and nucleases, is used to inhibit microbial production of VFAs, optionally combined with surfactants, chelators, or sequestrants, to treat cellulosic materials in papermaking processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If water loop closure is implemented to maximize water reuse, then water efficiency and environmental compliance are improved, but VFA accumulation and microbial growth increase
Solution Approach 1:
The patent converts the harmful effect of starch degradation into a beneficial process by introducing amylase enzymes that control and direct the breakdown of starch into sugars, which are then consumed by aerobic bacteria to produce harmless substances instead of VFAs. This transforms the harmful anaerobic degradation pathway into a controlled aerobic enzymatic process.
Solution Approach 2:
The patent introduces amylase enzymes as intermediary substances that mediate between starch and the microbial community. These enzymes act as catalysts that control the degradation pathway, preventing direct anaerobic breakdown and instead facilitating a controlled aerobic process that eliminates VFA formation while maintaining water loop closure benefits.
2Reliability
If biocides are used to control microbial growth, then bacterial growth is suppressed, but equipment corrosion and toxicity increase
Solution Approach 1:
The patent replaces the mechanical/chemical warfare approach of biocides with a biological enzymatic system. Instead of using toxic chemicals to kill bacteria, the process uses amylase enzymes to control starch degradation and aerobic bacteria to consume sugars, substituting chemical destruction with controlled biological metabolism that eliminates harmful VFAs without corroding equipment.
Solution Approach 2:
The patent changes the chemical parameters of the system by introducing enzymes that alter the degradation pathway of starch. This parameter change shifts the process from anaerobic to aerobic metabolism, fundamentally changing how microbial growth is controlled - not by killing bacteria but by controlling their metabolic pathway to prevent VFA production.
3Productivity
If starch is used as a nutritive substance for microbes, then microbial growth is promoted, but VFA production and odor increase
Solution Approach 1:
The patent applies preliminary action by introducing amylase enzymes before microbial degradation occurs. These enzymes pre-break down starch into sugars in a controlled manner, ensuring that when microbes consume the sugars, they do so aerobically and produce harmless substances rather than VFAs. This preliminary enzymatic breakdown prevents the harmful anaerobic pathway from occurring.
Solution Approach 2:
The patent converts the potentially harmful effect of starch as a nutritive substance into a beneficial process. By introducing amylase enzymes, the starch degradation is transformed from an uncontrolled anaerobic process that produces VFAs into a controlled aerobic enzymatic process that produces sugars for beneficial microbial consumption, eliminating odor and contamination issues.
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
The method effectively reduces VFA production, improving starch content, runnability, and strength properties in paper products while minimizing odors and equipment corrosion, using environmentally friendly agents.
Implementation Method 1
microbes present in the system produce amylases, which are enzymes capable of hydrolyzing starch into simpler sugar constituents
Implementation Method 2
under anaerobic conditions many microorganisms will further metabolize such sugars and produce volatile fatty acids (VFA)
Data Source
AI summary
A method of controlling volatile fatty acid (VFA) content in a pulp, paper, and/or board making processes is disclosed. The method may be used to provide process improvements in the form of reduced microbial contamination and odor, reduced starch degradation, optimized retention, and improved runability. The method includes treating a process flow comprising a cellulosic material comprising a starch with an enzymatic VFA control agent. The enzymatic VFA control agent is non-biocidal, may further comprise a surfactant or dispersant, and is utilized in an amount sufficient to inhibit microbiological production of one or more VFA. The method optionally includes treating the process flow with a biocidal agent in combination with the enzymatic VFA control agent. A composition for carrying out the method is also disclosed.