Growth of Penicillium rubens after desiccation Citation for published version (APA): Bekker, M. (2014). Growth of Penicillium rubens after desiccation. Technische Universiteit Eindhoven. https://doi.org/10.6100/IR774541 DOI: 10.6100/IR774541 Document status and date: Published: 01/01/2014 Document Version: Publisher’s PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above, please follow below link for the End User Agreement: www.tue.nl/taverne Take down policy If you believe that this document breaches copyright please contact us at: [email protected] providing details and we will investigate your claim. Download date: 04. Oct. 2021 Growth of Penicillium rubens after desiccation Mirjam Bekker Growth of Penicillium rubens after desiccation PROEFSCHRIFT ter verkrijging van de graad van doctor aan de Technische Universiteit Eindhoven, op gezag van de rector magnificus prof.dr.ir. C.J. van Duijn, voor een commissie aangewezen door het College voor Promoties, in het openbaar te verdedigen op maandag 26 mei 2014 om 16:00 uur door Mirjam Bekker geboren te Amsterdam Dit proefschrift is goedgekeurd door de promotoren en de samenstelling van de promotiecommissie is als volgt: voorzitter: prof.dr.ir. G.M.W. Kroesen 1e promotor: prof.dr.ir. O.C.G. Adan 2e promotor: prof.dr. H.A.B. Wösten (Utrecht University) copromotor(en): dr.ir. H.P. Huinink leden: dr.ir. G. Strijkers prof.dr.ir. G. Roels (KU Leuven) prof.dr. A-C. Ritschkoff (VTT Finland) prof.dr. P.J. Punt (Leiden University) voor mijn ouders ISBN 978-90-8891-873-5 Cover image editing by Joost Hecker Fotografie Cryo-SEM images throughout this thesis by Jan Dijksterhuis and Mirjam Bekker Cover design: Proefschriftmaken.nl || Uitgeverij BOXPress Printed & Lay Out by: Proefschriftmaken.nl || Uitgeverij BOXPress Published by: Uitgeverij BOXPress, ’s-Hertogenbosch Copyright © by M. Bekker, all rights reserved. This work was financed and supported by the Netherlands organization for Applied Scientific Research (TNO). The research described in this thesis was performed at the Eindhoven University of Technology (TU/e) at the department of Applied Physics, within the group Transport in Permeable Media (TPM). The major part of the practical work was done at the Netherlands organization for Applied Scientific Research (TNO) in Delft, the Netherlands. The cryo-SEM experiments were done at the CBS-KNAW Fungal Biodiversity Centre in Utrecht, the Netherlands. The ESEM experiments were performed at the multi scale lab of the department of mechanical engineering at the TU/e. Contents Glossary 8 Chapter 1 Introduction 9 Chapter 2 Recovery of a Penicillium rubens colony after an extreme osmotic shock 23 Chapter 3 Quantifying growth of Penicillium rubens on building materials at controlled humidity 55 Chapter 4 Growth in response to desiccation of Penicillium rubens on gypsum 85 Chapter 5 Conidial germination of Penicillium rubens on gypsum 107 Chapter 6 Conclusions and Outlook 129 Summary 137 Samenvatting 141 Acknowledgements 145 List of Publications 149 Curriculum Vitae 151 7 Glossary apex: tip basipetal: from the apex downward to the base colony: mycelium consisting of connected hyphae conidium: asexual, non-motile fungal propagule conidiophore: specialized hypha on which conidiogenous cells are formed desiccation: the process of extreme drying exudate: liquid droplets excreted by mycelium hyaline: transparent hydrophilic: water attracting, or having affinity for water hydrophobic: water repelling hydrophobins: small proteins secreted by filamentous fungi, known for their ability to self- assemble into amphipathic monolayers at hydrophobic–hydrophilic interfaces hypha (plural hyphae): filament of a mycelium, either or not compartmentalized by septa isothermal condition: under constant temperature mycelium: a network of interconnected hyphae phylloplane fungi: fungi living on leaf surfaces relative humidity (RH): term used to describe the thermodynamic state of water in the air. Equals the ratio, expressed in percentage, between the actual water vapor density in the air, and the saturated water vapor density at the same temperature. metabolite: intermediates and products of metabolism mycotoxins: metabolites of fungi that are toxic for animals and humans septum: a structure that compartmentalize hyphae Woronin body: small organelles that can plug the central pores in septa water activity (aw): term used to describe the thermodynamic state of water in a solution or solid substrate. The water activity of a solution or substrate equals the relative humidity (expressed as a ratio) only when hygric equilibrium has been established and no net transfer of water vapor takes place. xerophilic fungi: fungi that can, or prefer to grow in dry environments 8 1 Introduction 9 Chapter 1 1.1 Fungi in our daily life Fungi are part of our daily life. To name some examples, the specific taste of French cheese as Roquefort or Camembert is due to the presence of fungi, and for the preparation and special taste of soybean products like tempeh, miso and soy sauce, a fungus is used for the fermentation process. Moreover, yeasts play an important role in the production of alcoholic beverages, such as beer and wine, and in our own kitchen we use different types of mushrooms to add taste to a dish. Fungi are also of great medical and industrial importance. For instance, the fungal genus Penicillium produces the beta-lactam antibiotic penicillin. The discovery of this antibiotic was one of the most important breakthroughs for mankind in treating infections. In 2004, worldwide annual sales of penicillin antibiotics were about US$ 8 billion and have only increased ever since (Barber et al., 2004). Nonetheless, fungal growth in our indoor environment is not desirable. Fungal defacement of surfaces, such as ceilings and walls, forms an aesthetic problem (Fig 1), and results in considerable costs for repair, maintenance and redecoration of constructions (Adan & Samson, 2011). More concerning, fungal growth in the indoor environment also may have consequences for the health of inhabitants (Dales & Miller, 2001; Flannigan, 2001; Mudarri & Fisk, 2007; Mueller et al., 2013). In Europe, it is estimated that 25 % of all social housing have problems with humidity and fungal growth (WHO Regional Office for Europe, 2007; Adan & Samson, 2011). For the US it is estimated that from the 21.8 million people with reported asthma, 21 % is attributed to fungal and dampness exposure in the indoor environment, being approximately 1.5 % of the entire population of the US (Mudarri & Fisk, 2007). Indoor and outdoor air contains small particles of different origin, such as dust, pollen grains, fungal spores and fungal fragments. Long term or elevated exposure to hyphal fragments, mycotoxins, and secondary metabolites produced by fungi can cause allergic reactions and respiratory infections (Miller, 1992; Dales & Miller, 2001; Green et al., 2011). Especially fungi such as Stachybotris chartarum and Chaetomium globosum are known for their adverse health effects, since they produce highly toxic secondary metabolites (Jarvis & Miller, 2005; Nielsen & Frisvad, 2011). Fig 1 Fungal defacement in the indoor environment. 10 Introduction 1.2 Fungi in the indoor environment Fungi disseminate via the air by spores and hyphal fragments (Fig 2). After landing on a suitable substrate, a new mycelium develops when favorable biotic and abiotic conditions 1 are met. With time, the mycelium will form new conidia (asexual) or spores (sexual). To illustrate this, a schematic life cycle of the fungal genus Penicillium is given in figure 2. Note that the sexual state for Penicillium species is rarely observed, and that their conidia are the main source of infection in the indoor environment. Fig 2 Life cycle of Penicillium species, illustrating both the sexual and asexual life cycle. Note that for Penicillium species the asexual cycle is most common, and their conidia are the main source of infection in the indoor environment. Drawing: courtesy of the CBS-KNAW Fungal Biodiversity Centre. Cladosporium, Penicillium, Aspergillus, Aureobasidium, Chaetomium, Acremonium, Ulocladium,