Bacteriocin-Producing LAB Co-Culture for Fermentation Contamination
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Solution Overview
Problem
Bacterial contamination in ethanol fermentation facilities is a persistent issue, leading to the heavy reliance on antibiotics, which raises concerns about resistant strains and antibiotic residues in fermentation products.
Innovation Solution
A co-culture of two distinct lactic acid bacteria cells, one capable of expressing a bacteriocin and immune to it, is used to limit microbial contamination during fermentation, potentially replacing antibiotics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antibiotics are used to prevent bacterial contamination during fermentation, then contamination is controlled, but resistant bacterial strains emerge and antibiotic residues contaminate fermentation products
Solution Approach 1:
The patent uses bacteriocin-producing LAB as an intermediary agent to control contamination. Instead of directly applying antibiotics to the fermentation process, the system employs beneficial LAB that produce bacteriocins to selectively inhibit contaminating bacteria while leaving the fermentation process intact. This intermediary approach eliminates the need for direct antibiotic addition, thereby preventing antibiotic residues and resistance development while maintaining effective contamination control.
Solution Approach 2:
The patent converts the potentially harmful effect of bacteriocins (which can inhibit bacterial growth) into a beneficial anti-contamination mechanism. By selecting LAB strains that naturally produce bacteriocins and conferring immunity to the desired fermentation organisms, the system transforms what could be a harmful substance into a selective tool that eliminates contaminants while protecting the fermentation process. The bacteriocins become a beneficial agent for contamination control without the drawbacks of conventional antibiotics.
2Object-affected harmful factors
If bacteriocin-producing LAB are used to limit contamination, then antibiotic use is reduced, but the system complexity increases due to coculture requirements
Solution Approach 1:
The patent makes the LAB strains multi-functional by engineering them to simultaneously perform fermentation and bacteriocin production. The same LAB organism that carries out the desired fermentation process also produces bacteriocins to inhibit contaminants. This eliminates the need for separate contamination control mechanisms and simplifies the overall system despite the sophisticated genetic engineering involved, as one organism performs multiple functions that would otherwise require separate systems.
Solution Approach 2:
The patent merges the contamination control function with the fermentation function by combining bacteriocin production capability into the fermentation-performing LAB strains. Instead of using separate agents for fermentation and contamination control, the system integrates both functions into a single coculture system where LAB both ferment substrates and produce antimicrobial compounds. This merging reduces the number of separate components needed and simplifies process management.
3Quantity of substance
If immunity genes are introduced into LAB to prevent bacteriocin self-toxicity, then the LAB can produce bacteriocin, but genetic modification complexity increases
Solution Approach 1:
The patent implements self-service by engineering the LAB to automatically produce their own immunity proteins alongside bacteriocins. The genetically modified LAB strains contain both the bacteriocin production genes and the immunity gene(s), allowing them to self-regulate and protect themselves from the toxic effects of the bacteriocins they produce. This self-service mechanism eliminates the need for external protection systems and simplifies the overall genetic design, as the organism manages its own toxicity issue internally.
Solution Approach 2:
The patent applies preliminary action by pre-introducing immunity genes into the LAB strains before bacteriocin production begins. The immunity proteins are constitutively expressed or pre-positioned in the cell, ensuring that protective mechanisms are in place before the bacteriocins become active. This preliminary preparation prevents self-toxicity from occurring and allows uninterrupted bacteriocin production, simplifying the genetic engineering process by eliminating the need for complex inducible systems or post-production protection measures.
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 co-culture effectively reduces microbial contamination during ethanol production, minimizing the use of antibiotics and preventing the emergence of resistant strains.
Implementation Method 1
Nisin's bactericidal effects occur through binding of the peptidoglycan precursor molecule, lipid II. This inhibits cell wall synthesis and generates pores in the cytoplasmic membrane
Implementation Method 2
Nisin-producing strains of Lactococcus lactis generate autoimmunity through the expression of a lipoprotein, NisI, which obstructs nisin from binding lipid II
Implementation Method 3
a three component ABC transporter encoded by the genes nisE, nisF, and nisG
Implementation Method 4
Both lactic acid bacteria cells are immune to the bacteriocin and are capable of making a fermented product (from a biomass)
Data Source
AI summary
The present disclosure concerns a co-culture of bacterial cells for making a fermented product from a biomass. The co-culture comprising a first recombinant lactic acid bacteria (LAB) cell expressing at least one bacteriocin and a second recombinant lactic acid bacteria (LAB) cell capable of converting, at least in part, the biomass into the fermented product. The second recombinant LAB cell is immune to the bacteriocin produced by the first recombinant LAB cell. The co-culture can be used, optionally in combination with a yeast host cell, to make a fermented product. The present disclosure also provides processes for making the fermented product by using the co-culture as wells kits and media comprising the co-culture.