Recombinant Microorganism Simultaneous Sugar Fermentation
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Solution Overview
Problem
Current methods for producing diols through microorganism fermentation from lignocellulosic biomass face challenges such as low productivity, high grain prices, and difficulty in diol separation due to catabolite repression, which slows sugar consumption and increases fermentation time.
Innovation Solution
Development of recombinant microorganisms with enhanced simultaneous fermentation ability of pentose and hexose, specifically Klebsiella oxytoca strains engineered to inhibit catabolite repression and overexpress enzymes involved in xylose metabolism, allowing for efficient metabolism of mixed sugars in lignocellulosic hydrolysates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If microorganisms are used for diol production from lignocellulosic biomass, then environmental friendliness is improved, but productivity is reduced due to catabolite repression
Solution Approach 1:
The patent modifies genetic parameters of the microorganism by introducing and overexpressing specific genes (xylA, xylB, xylC, xylD, xylE, xylF) involved in xylose metabolism. This genetic parameter change enables the microorganism to simultaneously ferment both hexose and pentose sugars, overcoming the catabolite repression limitation and improving diol production productivity while maintaining environmental friendliness
Solution Approach 2:
The patent creates a composite metabolic system within the microorganism by combining multiple gene expressions (xylA through xylF) that work together to enable complete xylose utilization. This composite genetic system allows simultaneous fermentation of mixed sugars from lignocellulosic biomass, resolving the contradiction between environmental benefits and production efficiency
2Productivity
If hexose is used first for metabolism, then glucose utilization is improved, but fermentation time increases due to sequential sugar consumption
Solution Approach 1:
The patent establishes continuous sugar utilization by enabling simultaneous fermentation of both hexose and pentose sugars through overexpression of xylose metabolism genes. This eliminates the idle period between hexose consumption and pentose consumption, maintaining continuous metabolic activity and reducing total fermentation time while improving overall sugar consumption rate
3Productivity
If pentose remains in fermentation broth, then sugar utilization is incomplete, but separation and purification becomes difficult
Solution Approach 1:
The patent enables the microorganism to self-consume all sugars including pentose completely through the introduced xylose metabolism pathway. By expressing genes xylA through xylF, the system achieves complete sugar utilization without residual pentose in the fermentation broth, thereby eliminating separation and purification difficulties while maintaining high sugar utilization efficiency
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 recombinant microorganisms demonstrate improved sugar consumption rates and increased diol production efficiency, reducing fermentation time and enhancing productivity while avoiding accumulation of pentose sugars, thus facilitating cost-effective diol production from lignocellulosic biomass.
Implementation Method 1
recombinant microorganism having simultaneous fermentation ability of at least two sugars in lignocellulosic hydrolysate
Implementation Method 2
overexpress enzymes involved in xylose metabolism
Data Source
AI summary
The present invention relates to a recombinant microorganism which is capable of simultaneously fermenting at least two sugars in a lignocellulosic saccharified liquid, and also capable of generating diol.