Aureobasidium pullulans Strains for Melanin-Free Bioproduct Production
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Solution Overview
Problem
Aureobasidium pullulans strains produce melanin-associated pigments that contaminate bioproducts, leading to increased production costs due to the need for extensive purification processes, which also results in loss of desired products.
Innovation Solution
Genetically modified strains of Aureobasidium pullulans lacking specific biosynthetic enzyme activities, such as mannitol-1-phosphate-dehydrogenase, mannitol-dehydrogenase, and polyketide-synthase, are developed to produce bioproducts like arabitol-liamocins and massoia lactone without melanin contamination, using strains like MpdKO, Mdh2KO, and PksKO, which are grown under conditions that suppress melanin production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If genetically modified strains lacking biosynthetic enzyme activities are used, then melanin contamination is reduced, but bioproduct yield may be affected
Solution Approach 1:
The patent removes specific biosynthetic enzyme genes (MPD1, MDH2, PKS) from the A. pullulans genome to eliminate melanin and unwanted bioproduct formation. This genetic extraction allows production of purified bioproducts without melanin contamination, directly resolving the contradiction between purity and yield by decoupling the melanin production pathway from the desired bioproduct synthesis pathways
Solution Approach 2:
The patent applies local quality modification by selectively deleting only the specific genes responsible for melanin biosynthesis (MPD1, MDH2, PKS) while preserving all other metabolic pathways. This targeted genetic modification ensures that only the problematic melanin production is eliminated, while the desired bioproduct synthesis remains intact, thus maintaining yield while improving purity
2Manufacturing precision
If extensive purification processes are used to remove melanin, then bioproduct purity is improved, but production cost increases and product loss occurs
Solution Approach 1:
The patent performs preliminary action by genetically modifying the strain beforehand to eliminate melanin production capability. This preemptive genetic modification prevents melanin contamination at the source, eliminating the need for subsequent extensive purification steps and associated product losses, thus resolving the contradiction between purity and substance loss
Solution Approach 2:
The patent converts the harmful effect of melanin production into a benefit by deleting the melanin biosynthetic genes. What was previously a contaminant requiring costly removal is transformed into a non-issue, as the modified strains inherently produce no melanin. This resolves the contradiction by eliminating the need for purification while maintaining purity
Data Source
AI summary
The present disclosure provides methods for producing bioproducts from novel genetically altered strains of Aureobasidium pullulans. Methods and materials for the construction of these strains, examination of the bioproducts and analysis and isolation of the bioproducts from genetically altered strains is provided. Genetically altered A. pullulans strains in which one or more genes encoding biosynthetic enzymes are knocked out is detailed and the benefits of using such strains described.