Xylose Fermentation System with Segmented Vessels
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Solution Overview
Problem
Current ethanol production from biomass, particularly from lignocellulosic feedstocks like corn cobs, corn plant husks, and stalks, faces inefficiencies in separating and fermenting xylose and glucose sugars due to the presence of inhibitory compounds like acetic acid, which hampers the yield and efficiency of cellulosic ethanol production.
Innovation Solution
A fermentation system is developed that pre-treats and separates biomass into a liquid component containing xylose and acetic acid, and a solids component with glucose, using a modified Saccharomyces cerevisiae yeast to ferment xylose into ethanol within a controlled temperature and pH range, optimizing the conditions for efficient ethanol recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If biomass is pre-treated and separated into liquid and solids components for fermentation, then the accessibility of sugars (xylose and glucose) is improved, but the presence of acetic acid in the liquid component creates inhibitory effects on fermentation efficiency
Solution Approach 1:
The fermentation process is segmented into two separate vessels: the first vessel handles xylose fermentation from the liquid component, while the second vessel handles glucose fermentation from the solids component. This segmentation allows independent optimization of fermentation conditions for each sugar type and isolates the inhibitory acetic acid effects to the first vessel, where they can be managed separately.
Solution Approach 2:
A modified Saccharomyces cerevisiae yeast strain serves as an intermediary that enables xylose fermentation in the presence of acetic acid. This genetically modified yeast acts as a mediator that can tolerate and function effectively despite the harmful acetic acid environment, converting xylose to ethanol even under inhibitory conditions.
2Device complexity
If conventional yeast is used for fermentation, then the process is simple, but xylose fermentation efficiency is low due to inability to ferment xylose effectively
Solution Approach 1:
The yeast strain parameters are changed through genetic modification to enable xylose fermentation capability. The modified Saccharomyces cerevisiae possesses altered metabolic parameters that allow it to utilize xylose as a substrate, transforming it from a non-fermenting organism to an efficient xylose-fermenting organism while maintaining overall process simplicity.
3Device complexity
If single-vessel fermentation is used, then the process is simpler, but the yield of ethanol from both xylose and glucose is reduced due to competitive inhibition and suboptimal conditions
Solution Approach 1:
The single fermentation vessel is segmented into two separate vessels, each optimized for specific sugar fermentation. The first vessel is optimized for xylose fermentation with modified yeast and controlled pH (4.5-6.0) to handle acetic acid presence, while the second vessel handles glucose fermentation from solids hydrolyzate. This segmentation maximizes ethanol yield from both sugar sources by eliminating competitive inhibition and allowing independent condition optimization.
Solution Approach 2:
The solids component undergoes preliminary acid hydrolysis treatment before being introduced to the second fermentation vessel, pre-converting cellulose to accessible glucose. This preliminary action ensures that when the solids reach the second vessel, glucose is immediately available for efficient fermentation, maximizing overall ethanol production.
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 enhances the efficiency and yield of ethanol production by effectively converting xylose into ethanol, while minimizing the impact of inhibitory compounds, thereby improving the overall biomass conversion process.
Implementation Method 1
using a yeast capable of fermenting xylose into ethanol
Data Source
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AI summary
A fermentation system configured to produce a fermentation product from biomass that has been pre-treated and separated into a first component and a second component is disclosed. The system comprises a first vessel configured to receive the first component and an ethanologen and a second vessel configured to propagate the ethanologen for supply to the first vessel. A biorefinery for producing a fermentation product from biomass is also disclosed. The biorefinery comprises a preparation system to prepare the biomass into prepared biomass; a pre-treatment system to pre-treat the prepared biomass with a dilute acid for separation into a first component from which pentose can accessed for fermentation and a second component from which hexose can be made available for fermentation; a first treatment system to treat the first component into a treated first component by removing removed components from the first component; a first fermentation system to produce a first fermentation product from the pentose; a distillation system to recover ethanol from the first fermentation product; and a treatment system to process removed components. The biomass comprises lignocellulosic material; the lignocellulosic material comprises at least one of corn cobs, corn plant husks, corn plant leaves and corn plant stalks. The first component comprises pentose; the pentose comprises xylose. The ethanologen is capable of fermenting xylose into ethanol.