Rasamsonia Recombination for Marker-Free Cellulase Production
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Solution Overview
Problem
Current methods for bioconversion of lignocellulosic biomass to fermentable sugars are hindered by high production costs and low hydrolytic efficiency of enzymes, limiting the commercialization of biomass bioconversion processes, and existing Rasamsonia strains are not suitable for efficient cellulase production on glucose as a carbon source.
Innovation Solution
A method for recombination at a target locus in Rasamsonia cells is developed, allowing for the insertion, substitution, or deletion of nucleic acid sequences to generate marker-free strains with increased efficiency for targeted integration of polynucleotides and reduced protease pepA activity, enhancing enzyme production and biodegradation of lignocellulosic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional transformation methods are used in Rasamsonia, then integration of polynucleotides occurs, but integration efficiency is low and marker residues remain
Solution Approach 1:
The patent uses a recombinase enzyme as an intermediary to facilitate site-specific recombination between polynucleotide sequences and target genomic loci. The recombinase mediates the integration process, enabling efficient and precise insertion without requiring traditional selectable markers, thus resolving the contradiction between integration efficiency and marker-free integration.
Solution Approach 2:
The patent changes the recombination mechanism from random integration to site-specific recombination by introducing specific recombination sites (attP and attB) and their corresponding recombinase. This parameter change in the integration mechanism dramatically improves both integration efficiency and precision while eliminating the need for marker genes.
2Productivity
If existing Rasamsonia strains are used for cellulase production on glucose, then enzyme production occurs, but production efficiency is low and protease activity is high
Solution Approach 1:
The patent extracts or removes the harmful protease pepA activity from the Rasamsonia system through genetic modification. By eliminating or reducing protease activity, the system prevents degradation of produced enzymes, thereby improving net cellulase production efficiency without requiring external protection measures.
Solution Approach 2:
The patent modifies specific local properties of the Rasamsonia strain by introducing site-specific recombination capabilities and reducing protease activity at particular genomic loci. This localized modification approach allows the strain to maintain high cellulase production while minimizing harmful protease activity, resolving the contradiction between productivity and harmful factors.
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 method enables the creation of marker-free Rasamsonia cells with improved enzyme production efficiency, specifically for cellulases, hemicellulases, and pectinases, facilitating the biodegradation of lignocellulosic materials and the production of fermentable sugars for biofuels and industrial applications.
Implementation Method 1
sequences capable of homologous recombination with sequences flanking the target locus
Implementation Method 2
two or more site-specific recombination sites; a sequence encoding a recombinase which recognizes the site-specific recombination sites
Data Source
AI summary
The invention relates to a method for carrying out recombination at a target locus in a Rasamsonia cell. The invention also relates to Rasamsonia cells, for example Rasamsonia cells produced by such a process. The invention further relates to processes in which such Rasamsonia cells are used and to the resulting enzyme compositions. The invention further relates to nucleic acid and amino acid sequences.