Papers by Martijn Castelein
a Centre f o r I n d u st ria l Biotechnology and Biocatalysis (InBio.be) | b Center f o r Micro ... more a Centre f o r I n d u st ria l Biotechnology and Biocatalysis (InBio.be) | b Center f o r Micro b ia l Ecology and Technology (CME T ) | c Vito, Waste Recycling Technologies d TECNALIA, Energy and Environment Division | e Laboratory o f Analytical Chemistry and Applied Ecochemistry (ECOCHEM) | f Bio Base Europe P ilo t Plant, BE
Improved production of novel (bola) glycolipid biosurfactants with the yeast Starmerella bombicola through an integrative approach combining genetic engineering and multiomics analyses
Elsevier eBooks, 2023
Microbial Cell Factories
Background Plastics are an indispensable part of our daily life. However, mismanagement at their ... more Background Plastics are an indispensable part of our daily life. However, mismanagement at their end-of-life results in severe environmental consequences. The microbial conversion of these polymers into new value-added products offers a promising alternative. In this study, we engineered the soil-bacterium Comamonas testosteroni KF-1, a natural degrader of terephthalic acid, for the conversion of the latter to the high-value product 2-pyrone-4,6-dicarboxylic acid. Results In order to convert terephthalic acid to 2-pyrone-4,6-dicarboxylic acid, we deleted the native PDC hydrolase and observed only a limited amount of product formation. To test whether this was the result of an inhibition of terephthalic acid uptake by the carbon source for growth (i.e. glycolic acid), the consumption of both carbon sources was monitored in the wild-type strain. Both carbon sources were consumed at the same time, indicating that catabolite repression was not the case. Next, we investigated if the acti...
Sophorolipids: the natural functions unravelled
International Conference on Biobased Surfactants, 2020
The yeast Starmerella bombicola distinguishes itself from other non-conventional yeasts by its po... more The yeast Starmerella bombicola distinguishes itself from other non-conventional yeasts by its potential of producing copious amounts of the secondary metabolites sophorolipids. Secondary metabolites are typically produced by microorganisms in the stationary phase and are not required for growth. They perform a plethora of specific natural functions such as inhibiting growth of competing organisms by the many antibiotics produced by e.g. Actinobacteria; or increasing the availability of scarce soluble iron to the microorganism by metal chelating siderophores. Although sophorolipids have been the subject of numerous of research papers and have also been commercialized e.g. in eco-friendly cleaning solutions and cosmetics, the natural function of SLs for its producing organism S. bombicola remains elusive. Several hypotheses therefor are found in literature but very few or no experimental data is present to support or refute these. Five main hypotheses have been stated throughout the past 60 years: (1) SL production constitutes an overflow metabolism; (2) SLs exert antimicrobial activity, thereby resulting in niche protection by inhibition of the growth of competing microorganisms; (3) SLs improve the dissimilation of hydrophobic substrates; (4) SL production is a protection mechanism against high osmotic pressure; and (5) SLs serve as an extracellular storage compound of carbon and energy. Intrigued by this fundamental question, we investigated all abovementioned hypotheses trying to resolve this mystery and deliver the answer to the most asked question in the SL field: why does Starmerella bombicola produce sophorolipids
Frontiers in bioengineering and biotechnology, Feb 14, 2024
Sophorolipids, glycolipid biosurfactants derived from microorganisms such as Starmerella bombicol... more Sophorolipids, glycolipid biosurfactants derived from microorganisms such as Starmerella bombicola, possess distinctive surface-active and bioactive properties, holding potential applications in cosmetics, pharmaceuticals and bioremediation. However, the limited structural variability in wild-type sophorolipids restricts their properties and applications. To address this, metabolic engineering efforts have allowed to create a portfolio of molecules. In this study, we went one step further by chemically modifying microbially produced sophorosides, produced by an engineered S. bombicola. Twenty-four new sophoroside derivatives were synthesized, including sophoroside amines with varying alkyl chain lengths (ethyl to octadecyl) on the nitrogen atom and their corresponding quaternary ammonium salts. Additionally, six different microbially produced glycolipid biosurfactants were hydrogenated to achieve fully saturated lipid tails. These derivatives, along with microbially produced glycoli...
Improved production of novel (bola) glycolipid biosurfactants with the yeast Starmerella bombicola through an integrative approach combining genetic engineering and multiomics analyses
Elsevier eBooks, 2023
Yeast-made biobased glycolipid surfactants : their use in leaching from copper slags and tailings
The 17th edition of the International Conference on Renewable Resources & Biorefineries, Abstracts, 2021
Improved production of novel (bola) glycolipid biosurfactants with the yeast Starmerella bombicola through an integrative approach combining genetic engineering and multiomics analyses
Biosurfactants
From bumblebee to bioeconomy: Recent developments and perspectives for sophorolipid biosynthesis
Biotechnology Advances
A microbial assay of novel glycolipid biosurfactants produced by the yeast Starmerella bombicola
Journal of Fungi
The yeast Starmerella bombicola distinguishes itself from other yeasts by its potential of produc... more The yeast Starmerella bombicola distinguishes itself from other yeasts by its potential of producing copious amounts of the secondary metabolites sophorolipids (SLs): these are glycolipid biosurfactants composed out of a(n) (acetylated) sophorose moiety and a lipid tail. Although SLs are the subject of numerous research papers and have been commercialized, e.g., in eco-friendly cleaning solutions, the natural function of SLs still remains elusive. This research article investigates several hypotheses for why S. bombicola invests that much energy in the production of SLs, and we conclude that the main natural function of SLs in S. bombicola is niche protection: (1) the extracellular storage of an energy-rich, yet metabolically less accessible carbon source that can be utilized by S. bombicola upon conditions of starvation with (2) antimicrobial properties. In this way, S. bombicola creates a dual advantage in competition with other microorganisms. Additionally, SLs can expedite growt...
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Papers by Martijn Castelein