Juliana Lebeau | University of Nottingham (original) (raw)

Papers by Juliana Lebeau

Applied microbiology and biotechnology, 2014

Marine sponges harbor diverse microbial communities, encompassing not only three domains of life ... more Marine sponges harbor diverse microbial communities, encompassing not only three domains of life including Bacteria, Archaea and eukaryotes, but also many different phyla within Bacteria. This diversity implies a rich source for biodiscovery of new natural products. Here, we review recent progress in our understanding of this genetic diversity, its retrieval via culture and genomic approaches, and its implications for chemical diversity and other biotechnology applications of sponge microorganisms and their genes.

Frontiers in Bioengineering and Biotechnology, Mar 20, 2020

Industrial biotechnology can lead to new routes and potentially to more sustainable production of... more Industrial biotechnology can lead to new routes and potentially to more sustainable production of numerous chemicals. We review the potential of biobased routes from sugars to the large volume commodity, methacrylic acid, involving fermentation based bioprocesses. We cover the key progress over the past decade on direct and indirect fermentation based routes to methacrylic acid including both academic as well as patent literature. Finally, we take a critical look at the potential of biobased routes to methacrylic acid in comparison with both incumbent as well as newer greener petrochemical based processes.

Life, Nov 30, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Journal of Fungi, 2017

The use of ascomycetous fungi as pigment producers opens the way to an alternative to synthetic d... more The use of ascomycetous fungi as pigment producers opens the way to an alternative to synthetic dyes, especially in the red-dye industries, which have very few natural pigment alternatives. The present paper aimed to bio-prospect and screen out 15 selected ascomycetous fungal strains, originating from terrestrial and marine habitats belonging to seven different genera (Penicillium, Talaromyces, Fusarium, Aspergillus, Trichoderma, Dreschlera, and Paecilomyces). We identified four strains, Penicillium purpurogenum rubisclerotium, Fusarium oxysporum, marine strains identified as Talaromyces spp., and Trichoderma atroviride, as potential red pigment producers. The extraction of the pigments is a crucial step, whereby the qualitative and quantitative compositions of each fungal extract need to be respected for reliable identification, as well as preserving bioactivity. Furthermore, there is a growing demand for more sustainable and cost-effective extraction methods. Therefore, a pressurized liquid extraction technique was carried out in this study, allowing a greener and faster extraction step of the pigments, while preserving their chemical structures and bioactivities in comparison to conventional extraction processes. The protocol was illustrated with the production of pigment extracts from P. purpurogenum rubisclerotium and Talaromyces spp. Extracts were analyzed by high-performance liquid-chromatography combined with photodiode array-detection (HPLC-DAD) and high-resolution mass spectrometry (UHPLC-HRMS). The more promising strain was the isolate Talaromyces spp. of marine origin. The main polyketide pigment produced by this strain has been characterized as N-threoninerubropunctamine, a non-toxic red Monascus-like azaphilone pigment.

Pigments and Colorants from Filamentous Fungi

Fungal Metabolites, 2015

Biotechnology Progress, 2018

Filamentous fungi have gained growing interest as sources of diverse pigmented secondary metaboli... more Filamentous fungi have gained growing interest as sources of diverse pigmented secondary metabolites. Some specific polyketides from Ascomycetous species have demonstrated a wide range of industrial applications in food, cosmetic, textile and in the design of pharmaceutical products. The formulation of recipes containing fungal polyketides has increased over recent years. Fusarium strains were proven useful to mankind in a variety of technologies. Nevertheless, there is still need of new isolates of Fusarium for use in emerging and already existing fields. In this article we report the concomitant production of the bioactive red bikaverin along with two novel purple pigments by the phytopathogenic Fusarium oxysporum LCP531 strain isolated from soil. In literature, the production of purple pigment had only been described in cultures of F. Fujikuroi, F. verticillioides and F. graminearum. The production of these naphthoquinonic pigments, their distribution (either produced in mycelia or excreted in liquid medium) and their chemical profiles were investigated with respect to nutrient composition. The pigments were extracted by using a pressurized liquid extraction method, monitored by colorimetric analysis and characterized by HPLC-DAD chromatography. To our knowledge, this is the first report of these two novel wild-type purple naphtoquinones pigments along with bikaverin, where additionally, the culture conditions were put into perspective in order to optimize fermentation cultures and extraction process accordingly to the pigment/biomolecule desired. These colored naphthoquinones should be Accepted Article This article is protected by copyright. All rights reserved. Thi s article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

Microorganisms, 2020

Many species of Talaromyces of marine origin could be considered as non-toxigenic fungal cell fac... more Many species of Talaromyces of marine origin could be considered as non-toxigenic fungal cell factory. Some strains could produce water-soluble active biopigments in submerged cultures. These fungal pigments are of interest due to their applications in the design of new pharmaceutical products. In this study, the azaphilone red pigments and ergosterol derivatives produced by a wild type of Talaromyces sp. 30570 (CBS 206.89 B) marine-derived fungal strain with industrial relevance were described. The strain was isolated from the coral reef of the Réunion island. An alternative extraction of the fungal pigments using high pressure with eco-friendly solvents was studied. Twelve different red pigments were detected, including two pigmented ergosterol derivatives. Nine metabolites were identified using HPLC-PDA-ESI/MS as Monascus-like azaphilone pigments. In particular, derivatives of nitrogen-containing azaphilone red pigment, like PP-R, 6-[(Z)-2-Carboxyvinyl]-N-GABA-PP-V, N-threonine-m...

Improving the carbon efficiency in the bio-production of citramalic acid in Escherichia coli

Methacrylic acid (MAA) is a bulk chemical used in the synthesis of acrylic polymers as well as fo... more Methacrylic acid (MAA) is a bulk chemical used in the synthesis of acrylic polymers as well as for the manufacture of many different products such as resins, and paints. However, the industrial manufacturing processes for MAA production involve toxic raw materials that are reliant on availability and economic variability of petroleum derived compounds. Global consumption and market of acrylics keep growing, rendering constant production processes as well as price stability highly desirable. To date, there is no direct bio-process available for the biosynthesis of MAA itself. Fortunately, a bio-production route of citramalic acid, which was previously demonstrated to be converted readily to MAA in a simple chemical patented hot pressurised water process, was demonstrated in Escherichia coli with promising titres of product (130 g/L). The enzyme citramalate synthase was used, and catalysed the condensation of two central cellular metabolites, pyruvate and acetyl-CoA, to (R)-citramalat...

Extraction of fungal polyketide pigments using ionic liquids

Filamentous fungi have been widely recognized as promising sources of various types of biomolecul... more Filamentous fungi have been widely recognized as promising sources of various types of biomolecules and are therefore highly investigated. The production of fungal pigments is one intensively studied domain in order to respond to the growing demand for natural colorants as substitutes to synthetic dyes used in food, cosmetics, pharmaceutical and textile industries. Such interest in the natural origins of the pigments is driving the search for new and greener extraction systems. It is desired to develop extraction processes that would use less organic solvents and milder conditions, allow higher and quicker extraction yields, as well as improved selectivity and better recovery. Over the last two decades, ionic liquids (ILs) have caught attention as novel green solvents, and have already been applied in various separation systems (membranes separation, additives in mobile phase and surface-bonded stationary phases in chromatography) [1]. ILs are molten salts that can display a vast va...

Emerging greener extraction systems for fungal pigments isolation

Filamentous fungi produce a mixture of various metabolites such as pigments, fatty acids, protein... more Filamentous fungi produce a mixture of various metabolites such as pigments, fatty acids, proteins and other cellular metabolites. Thus, extraction and isolation of the pigmented molecules of interest are necessary steps before proceeding to any further utilization of these metabolites for commercial applications. Pigments can be stored within the biomass, excreted in the fermentation broth or both, suggesting that extraction methods need to be developed accordingly to the cellular localisation of the pigments and to their chemical natures. Despite the wide range of separation techniques currently available, most of industrial extraction processes rely on conventional liquid-liquid systems using organic solvent (hexane, dichloromethane, toluene, THF, etc.). Since environmental pollution generated by chemical industries has become a central concern in societal and political decisions, there is a growing demand for the development of efficient and greener separation technologies. Over...

A critical review on the progress and challenges to a more sustainable, cost competitive synthesis of adipic acid

Green Chemistry

A review of recent developments and remaining challenges to the development of greener, cost comp... more A review of recent developments and remaining challenges to the development of greener, cost competitive processes for adipic acid manufacture. Chemical and biotechnological processes from both petroleum based and renewable feedstocks are reviewed.

Escherichia coli Cas1/2 Endonuclease Complex Modifies Self-Targeting CRISPR/Cascade Spacers Reducing Silencing Guide Stability

ACS Synthetic Biology

TheE. coliCas1/2 endonuclease complex reduces CRISPR/Cascade guide array stability

CRISPR based interference has become common in various applications from genetic circuits to dyna... more CRISPR based interference has become common in various applications from genetic circuits to dynamic metabolic control. InE. colithe native CRISPR Cascade system can be utilized for silencing by deletion of thecas3nuclease along with expression of guide RNA arrays, where multiple genes can be silenced from a single transcript. We notice the loss of protospacer sequences from guide arrays utilized for dynamic silencing. We report that unstable guide arrays are due to expression of the Cas1/2 endonuclease complex. Acas1deletion improves guide array stability. We propose a model wherein basal Cas1/2 endonuclease activity results in the loss of protospacers from guide arrays. Subsequently, mutant guide arrays can be amplified through selection. Replacing a constitutive promoter driving Cascade complex expression with a tightly controlled inducible promoter improves guide array stability, while minimizing leaky gene silencing.HighlightsCas1/2 endonuclease complex mediates CRISPR/Cascade ...

Alternative sources of red dyes with high stability and antimicrobial properties: Towards an ecological and sustainable approach for five plant species from Madagascar

Journal of Cleaner Production

Dynamic control over feedback regulation identifies pyruvate-ferredoxin oxidoreductase as a central metabolic enzyme in stationary phase E. coli

We demonstrate the use of two-stage dynamic metabolic control to manipulate feedback regulation i... more We demonstrate the use of two-stage dynamic metabolic control to manipulate feedback regulation in central metabolism and improve stationary phase biosynthesis in engineered E. coli. Specifically, we report the impact of dynamic control over two enzymes: citrate synthase, and glucose-6-phosphate dehydrogenase, on stationary phase fluxes. Firstly, reduced citrate synthase levels lead to a reduction in α-ketoglutarate, which is an inhibitor of sugar transport, resulting in increased stationary phase glucose uptake and glycolytic fluxes. Reduced glucose-6-phosphate dehydrogenase activity activates the SoxRS regulon and expression of pyruvate-ferredoxin oxidoreductase, which is in turn responsible for large increases in acetyl-CoA production. The combined reduction in citrate synthase and glucose-6-phosphate dehydrogenase, leads to greatly enhanced stationary phase metabolism and the improved production of citramalic acid enabling titers of 126±7g/L. These results identify pyruvate oxid...

Two-stage Dynamic Deregulation of Metabolism Improves Process Robustness Scalability in Engineered E. coli

We report improved strain and bioprocess robustness as a result of the dynamic deregulation of ce... more We report improved strain and bioprocess robustness as a result of the dynamic deregulation of central metabolism using two-stage dynamic control. Dynamic control is implemented using combinations of CRISPR interference and controlled proteolysis to reduce levels of central metabolic enzymes in the context of a standardized two-stage bioprocesses. Reducing the levels of key enzymes alters metabolite pools resulting in deregulation of the metabolic network. The deregulated network is more robust to environmental conditions improving process robustness, which in turn leads to predictable scalability from high throughput small scale screens to fully instrumented bioreactors as well as to pilot scale production. Additionally, as these two-stage bioprocesses are standardized, a need for traditional process optimization is minimized. Predictive high throughput approaches that translate to larger scales are critical for metabolic engineering programs to truly take advantage of the rapidly ...

Frontiers in Bioengineering and Biotechnology

AMB Express

Fungal naphthoquinones, like red bikaverin, are of interest due to their growing applications in ... more Fungal naphthoquinones, like red bikaverin, are of interest due to their growing applications in designing pharmaceutical products. Though considerable work has been done on the elucidation of bikaverin biosynthesis pathway in Fusarium fujikuroi, very few reports are available regarding its bioproduction in F. oxysporum. We are hereby proposing a putative metabolic pathway for bikaverin bioproduction in a wild F. oxysporum strain by cross-linking the pigment profiles we obtained under two different fermentation conditions with literature. Naphthoquinone pigments were extracted with a pressurized liquid extraction method, and characterized by HPLC–DAD and UHPLC-HRMS. The results led to the conclusions that the F. oxysporum LCP531 strain was able to produce bikaverin and its various intermediates, e.g., pre-bikaverin, oxo-pre-bikaverin, dinor-bikaverin, me-oxo-pre-bikaverin, and nor-bikaverin, in submerged cultures in various proportions. To our knowledge, this is the first report of ...