Prof. dr. H.A.B. (Han) Wösten

Hugo R. Kruytgebouw
Padualaan 8
Kamer O.401
3584 CH Utrecht

Prof. dr. H.A.B. (Han) Wösten

Professor
Molecular Microbiology
+31 30 253 3448
h.a.b.wosten@uu.nl

Research lines

  • Research line I focusses on heterogeneity between and within fungal bodies (i.e. mycelia). We mainly use Aspergillus as a model system. We have shown that a mycelium does not consist of a collection of identical cells (hyphae) but rather consists of different hyphal types, for instance hyphae that secrete enzymes to degrade organic material that serves as food. Why and how fungi form heterogeneous mycelium is being studied. This is not only because of fundamental interest it is also a target to improve fungi as cell factories for the production of enzymes, medicine and other compounds.
  • Research line II focusses on development of mushrooms. We study the regulatory proteins that control mushroom formation as well as the genes that are regulated by these proteins. In addition, we study the impact of environmental conditions (e.g. light and CO2 levels) on mushroom formation. This study is of fundamental interest but is also important for the industry producing edible or medicinal mushrooms. For instance, our research resulted in a white button mushroom strain that start to form mushrooms 1 day earlier when compared to the current production strain.
  • Research line III focusses on the development of sustainable materials out of mycelia. To this end we for instance collaborate with Mogu, Neffa, and Avans Hogeschool. For more details I refer to a radio interview or a documentary from Motherboard 
  • Research line IV focusses on production and stress resistance of fungal spores. We study the underlying mechanisms of stress resistance. At the same time, we study the signals that break dormancy of fungal spores. This research is of fundamental interest but is also relevant to prevent fungal spoilage.
  • We also have research lines on fungal human pathogens (Hans de Cock) and Functional Genomics (Robin Ohm)
Completed Projects
Project
Fungar 01.12.2019 to 30.11.2022
General project description

Cross-disciplinary research project that seeks to develop a fully integrated structural and computational living substrate using fungal mycelium for the purpose of growing architecture. Fungar website

Role
Researcher
Funding
EU grant Horizon 2020 research and innovation programme
External project members
  • Unconventional Computing Laboratory at University of the West of England (UWE)
  • Centre for Information Technology and Architecture (CITA) at Royal Danish Academy
  • MOGU
Project
Removing toxic micropollutants from waste water with fungi 01.09.2018 to 31.08.2023
General project description

Micropollutants that are present in surface water bodies have high risk for the environment. These toxic compounds originate from industrial and agricultural activities and activities of individuals. They include heavy metals and polycyclic aromatic hydrocarbons (PAHs) such as industrial chemicals, dyes, pesticides, pharmaceuticals, personal care products, and steroid hormones. Removing micropollutants from waste water helps to protect nature and the human population. Current waste water treatment plants (WWTPs) are not able to degrade these micropollutants effectively. They are therefore removed by reverse osmose filtration (RO) to produce drinking water. This results in a waste stream with a 3-5 fold higher concentration of micropollutants and ammonium. This concentrate is returned to WWTPs and finally, is returned to surface water bodies. Here, we aim to purify RO waste water from micropollutants using the mycelium of mushroom forming white rot fungi (WRFs).

WRF are main contributors of carbon cycling in nature by degrading the highly recalcitrant lignin in plant waste. Lignin, the second most abundant natural polymer after cellulose, consists of complex PAHs that are degraded by WRFs by secreting lignin oxidases (LO family) and lignin-degrading auxiliary enzymes (LDA family). These oxidizing enzymes can also degrade other PAHs, including micropollutants. Yet, it is not clear which individual enzymes are responsible for degradation of each PAH. Notably, WRF also adsorb and accumulate heavy metals. The resistance to these toxic compounds differs between species and the underlying mechanism(s) are poorly understood.

Apart from micropollutants, water needs to be purified from ammonium (NH4+). It promotes growth of algae and duckweed and thereby affects biodiversity. Moreover, NH4+ can dissociate in NH3 and H+. NH3 can be toxic for instance for fish. Since fungi can use ammonium as nitrogen source, detoxification of micropollutants can be combined with conversion of ammonium in biomass. This could thus be a positive side effect of the purification from micropollutants.

In this project, we will systematically assess the degrading and sorbing activities of micropollutants by mushroom forming WRFs and will for the first time study the molecular mechanisms that explain the differences in these activities between these fungi. Knowledge of these mechanisms will enable us to design a water purification system.

Role
Researcher
Funding
Other the Dutch water company Oasen and Utrecht University
Project members UU
External project members
  • prof.dr.ir. W.G.J. van der Meer
Project
Research Through Design 01.07.2016 to 01.07.2019
General project description

One of the challenges of this century is to transform our current economy into an eco-friendly and self-sustaining system. An innovative approach is the use of mycelium for the development of materials. Mycelium is an interwoven network of fungal filamentous cells called hyphae. Fungi form these mycelia on a wide variety of organic substrates. Mushroom forming fungi are known for their efficient colonization of ligno-cellulosic substrates like wood and straw. In a project of NWO Creative Industry we have developed sub-millimeter to centimeter thick layers of pure mycelium of a mushroom forming fungus. Depending on growth conditions and treatment, materials have been obtained that resemble paper, rubber, plastic and wood.

Composite biomaterials are achieved by growing mycelium of mushroom forming fungi organisms as Schizophyllym commune (split gill fungus), in a matrix of organic material such a s saw dust. The resulting materials resemble cork and wood and were used to make panels and objects. In this project, we aim to develop a palette of mycelium-based composite materials with different physical properties. Designers, artists, producers and end-users will explore the potential of the materials and will provide feedback how to improve the properties of the mycelium. This should result in tailor-made mycelia for innovative design solutions and new concepts of sustainable materials.

Role
Researcher
Funding
NWO grant STW
External project members
  • M. (Maurizio) Montalti Msc Design Academy Eindhoven (DEA)
  • dr. E. (Elvin) Karana Design Engineering Delft University of Technology (TUD)
Project
Identity of compartments within a fungal hypha 01.06.2014 to 31.05.2018
General project description

Fungi form a mycelium of interconnected hyphae that grow and secrete at their tips and that branch sub-apically. Hyphae of most fungi are compartmentalized by septa that have pores with a diameter > 100 nm. These pores allow translocation of cytosol and even organelles within and between hyphae. Therefore, it was generally believed that the cytoplasm within a mycelium is continuous. This also explained why multiple compartments support the growth process at the hyphal tip. However, we have recently shown that septal pores can be closed in growing hyphae by means of specialized organelles. Closure is a dynamic process that is influenced by environmental conditions. This raises the questions whether compartments have their own molecular and functional identity, whether this identity results in functional synergism, and how closure of septal pores impacts these processes. These questions will be addressed in this proposal using Aspergillus niger as a model system. This fungus is widely used by the industry for the production of proteins and metabolites. We will use highly innovative technologies including life time imaging of protein translocation in hyphae and single cell expression analysis. In fact, we recently were the first who successfully adopted whole genome single cell expression analysis in a microbe. The results of this study are not only of fundamental importance, they may also provide insights how Aspergillus niger, and other fungi, can be improved as a cell factory.

Role
Researcher
Funding
NWO grant NWO
External project members
  • dr. R. B. J. Bleichrodt