Fermentation Mash Oxidant Control for Lactic Acid Bacteria
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Solution Overview
Problem
Conventional antibiotics used in ethanol production systems to control lactic acid bacteria carry over into distillers grains, leading to animal feed contamination, antibiotic resistance, and reduced ethanol production efficiency, prompting a need for alternative antimicrobial solutions.
Innovation Solution
Introducing organic oxidizing compounds like peracetic acid and inorganic oxidizing compounds such as hydrogen peroxide into the fermentation mash to control lactic acid bacteria levels without using antibiotics, ensuring these compounds decompose and do not carry over into distillers grains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antibiotics are added to control lactic acid bacteria, then lactic acid levels are reduced, but antibiotics carry over into distillers grains causing contamination and resistance
Solution Approach 1:
The patent applies strong oxidizing agents (peracetic acid and hydrogen peroxide) to eliminate lactic acid bacteria through oxidation rather than antibiotic inhibition. These oxidants generate reactive oxygen species that damage bacterial cell structures and metabolic processes, effectively controlling lactic acid production without the carryover problems of antibiotics.
Solution Approach 2:
The patent changes the chemical parameter approach from antibiotic-based biological inhibition to oxidant-based chemical destruction. By introducing oxidizing compounds with different chemical mechanisms, the system achieves bacterial control while avoiding the persistence and resistance issues associated with antibiotics in the fermentation process.
2Reliability
If antibiotics are used continuously, then lactic acid bacteria are controlled initially, but bacteria develop resistance over time reducing effectiveness
Solution Approach 1:
Oxidizing agents attack multiple cellular targets simultaneously (cell wall, cell membrane, proteins, DNA) through non-specific oxidative damage, making it difficult for bacteria to develop resistance. This multi-target mechanism prevents the adaptive response that occurs with single-target antibiotic action.
Solution Approach 2:
The oxidizing agents are used at controlled doses and decompose into harmless byproducts (acetic acid, water, oxygen), creating a temporary but effective action that doesn't persist in the system. This short-lived action prevents long-term exposure that would select for resistant strains.
3Reliability
If antibiotics are added to fermentation mash, then acid bacteria growth is inhibited, but yeast growth is also affected and ethanol production decreases
Solution Approach 1:
The oxidizing agents are applied at specific locations and times in the fermentation process (added to fermentation mash at controlled dosing rates), creating localized treatment zones where bacterial control occurs without overwhelming the entire system. This allows selective pressure on bacteria while preserving yeast functionality in other areas.
Solution Approach 2:
The patent adjusts chemical parameters (oxidant concentration, pH, temperature) to create conditions favorable for yeast while inhibiting bacteria. By controlling the oxidation-reduction environment and maintaining appropriate pH levels, the system supports ethanol-producing yeast while the oxidants selectively damage acid-producing bacteria.
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 effectively reduces lactic acid levels, maintains high ethanol recovery, prevents biofouling, and extends equipment service life without contaminating distillers grains with antibiotics, enhancing the overall efficiency and safety of the fermentation process.
Implementation Method 1
introducing an organic oxidizing compound and an inorganic oxidizing compound into a fermentation mash
Implementation Method 2
ensuring these compounds decompose and do not carry over into distillers grains
Data Source
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AI summary
A system and method for controlling bacteria, especially lactic and acetic acid bacteria in the production of ethanol using an organic oxidizing compound in combination with an inorganic oxidizer is provided. Particularly, a mixture of one or more peroxy acids and one or more peroxide compounds is introduced into a fermentation mash so as to inhibit or reduce levels of bacteria that compete with yeast for the fermentation sugars. The peroxy acid and peroxide compounds largely are consumed during the fermentation process and are generally not present in the fermentation by-products, especially recovered distiller's grains.