Clostridium autoethanogenum Bacteria for Ethanol Fermentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current microbial fermentation processes for ethanol production from carbon monoxide (CO) gases suffer from inefficiencies, including co-production of acetate, which can lead to greenhouse gas emissions and reduced ethanol yield, especially when CO-containing gases have high CO and low H2 concentrations.
Innovation Solution
A novel biologically pure isolate of bacteria, such as Clostridium autoethanogenum strain LBS1560, capable of anaerobic fermentation of substrates with greater than 65% CO and less than 20% H2 by volume, achieving an ethanol to acetate ratio of at least 1.0 and producing ethanol concentrations up to 3.4 g/L, with enhanced productivity and reduced acetate production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional yeast-based fermentation processes are used to produce ethanol from carbohydrate feed stocks, then ethanol production is achieved, but the cost is influenced by the value of feed stocks as human food or animal feed and cultivation is not economically sustainable in all geographies
Solution Approach 1:
The patent changes the carbon source parameter from carbohydrate feed stocks to CO-containing gases, fundamentally altering the substrate type. This allows utilization of industrial waste gases (steel industry, coal gasification, biomass gasification) that are abundant and low-cost, eliminating the economic constraints of traditional crop-based fermentation
Solution Approach 2:
The patent uses bacterial fermentation pathways (acetyl-CoA pathway) that replicate the ethanol production capability traditionally associated with yeast, but applies it to a different substrate (CO gases instead of carbohydrates). This copying of the fermentation function on an alternative substrate enables sustainable ethanol production from non-food resources
2Productivity
If micro-organisms are used to convert CO gases into ethanol, then ethanol production from abundant carbon resources is achieved, but acetate is co-produced which reduces ethanol yield and can lead to greenhouse gas emissions
Solution Approach 1:
The patent optimizes the gas composition parameters (high CO concentration >65%, low H2 concentration <20%) to favor ethanol production pathways over acetate production. This parameter optimization shifts the metabolic balance toward ethanol, achieving ethanol to acetate ratios of at least 1.0:1, thereby reducing harmful emissions while maintaining productivity
Solution Approach 2:
The patent converts the previously harmful acetate by-product into a manageable component by optimizing conditions to minimize its formation. The acetate that is produced can be further utilized or disposed of, but the primary strategy is to convert the harmful emission problem into a controlled fermentation outcome with minimal acetate formation through precise gas composition control
3Adaptability or versatility
If conventional fermentation processes are used with high CO and low H2 concentrations, then substrate utilization is improved, but ethanol production efficiency decreases due to co-production of acetate
Solution Approach 1:
The patent identifies and optimizes specific parameter ranges for gas composition (CO >65%, H2 <20%) that simultaneously enable both substrate utilization and high ethanol productivity. This parameter optimization resolves the contradiction by finding the sweet spot where high CO tolerance does not compromise ethanol yield
Solution Approach 2:
The patent employs dynamic control of fermentation conditions, including pH control (maintaining pH 5.0-6.5), temperature control (30-40°C), and gas flow rate optimization, to adapt the fermentation process to the specific substrate composition. This dynamic adjustment ensures high ethanol production efficiency even when utilizing substrates with varying CO and H2 concentrations
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 bacteria efficiently convert CO-rich substrates into ethanol with improved ethanol to acetate ratios and productivity, reducing waste and greenhouse gas emissions, and can operate in the absence of H2, making the process more sustainable and economically viable.
Implementation Method 1
A novel biologically pure isolate of bacteria, such as Clostridium autoethanogenum strain LBS1560, capable of anaerobic fermentation of substrates with greater than 65% CO and less than 20% H2 by volume
Data Source
AI summary
A biologically pure isolate of a selected bacterium derived from Clostridium autoethanogenum is described which has improved efficiency in the production of ethanol by anaerobic fermentation of substrates comprising carbon monoxide. The bacterium can produce ethanol and acetate at an ethanol to acetate ratio of at least 1.0 and has a productivity of at least 1.2 g of ethanol/l of fermentation broth per day. The bacterium is also characterized in that it has substantially no ability to sporulate.