Associate ProfessorMichael Kertesz

Project Opportunities:

1. Title: The influence of microbial interactions on mushroom production

Summary of opportunity:

Mushrooms are an economically important food source with an annual retail value in Australia of almost $700 million. Although edible fungi have been grown for many years, knowledge of the physical and chemical nature of the substrate and related microbial processes is still relatively limited. The project will use modern genetic technology to investigate the dynamics of the active microbial community during compost production and subsequent mushroom cultivation.

Opportunity synopsis:

Traditionally, the two main components of mushroom compost are poultry manure and wheat straw, but the quality and availability of these components is increasingly uncertain. Changes to food sources used for poultry, especially from meat-based to grain-based diets, affect the levels of manure nitrogen available for mushroom growth, and wheat straw is often in short supply due to demand from other sectors. Mushroom growers have experimented in the past with alternative feedstocks, but because too little is known about the microbial processes taking place during compost production and subsequent mushroom cultivation, these experiments have often been costly and unsuccessful. The proposed Ph.D. project will examine the microbial processes occurring during compost production, aiming to identify the microorganisms that are key in converting raw materials and releasing the nutrients required for mushroom cultivation. It will then investigate the interactions of these organisms with the mushroom hyphae during growth, and how these stimulate yield and quality of the mushrooms themselves. The student will:

• Characterize the microbial succession during the commercial composting process, using molecular fingerprinting and next generation sequencing technology;
• Investigate a range of alternative feedstock substrates, correlating changes in microbial diversity with composting efficiency and mushroom yield, and designing appropriate microbial or enzymatic amendments to maximize these;
• Investigate the role of key microbial species in mushroom hyphal growth, and in the initiation of mushroom fruiting bodies (pinning).

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2. Title: Microbial nitrogen cycling and mushroom production

Summary of opportunity:

Mushrooms are an important food source in the Australian diet, supplying protein, vitamins and micronutrients. Growing nutrient-rich mushrooms requires a specialized compost, which is produced in a microbial process from wheat straw and poultry manure. The project will study microbial nitrogen cycling during composting and mushroom cropping, and how changes in microbial activity affect the nutritional content of the mushroom crop.

Opportunity synopsis:

The button mushrooms available in Australian supermarkets are grown commercially on a specialized mushroom compost produced from two main ingredients: wheat straw, which provides carbon for mushroom growth, and poultry manure, which provides nitrogen. However, bacterial activity during the high-temperature composting process often releases much of the nitrogen as ammonia or nitrous oxide gases, and supplementary nitrogen sources usually need to be added late in the process to replace the losses. Our recent work has characterized the active microbes (bacteria and fungi) that are responsible for converting the wheat straw into productive compost, and many of these are also highly active in catalyzing these reactions of nitrogen-containing compounds during composting. In order to reduce nitrogen losses and increase the nutrient yield in the final mushroom crop, we need to understand how the nitrogen levels in the compost are controlled by the compost microbes. The project will use modern analytical and molecular genetic methods to investigate the overall balance of nitrogen inputs and outputs during composting, and will explore how gene expression in the key compost microbes controls this process. Changes in nitrogen supplementation will be related to microbial activity and to overall crop yield and nutritional value. The project will make use of the University’s Marsh-Lawson Mushroom Research Unit, and will integrate laboratory and model studies with full scale experiments in close collaboration with industrial mushroom composters and mushroom producers in the Sydney basin.

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3. Title: Optimising hyphal fusion to build myco-materials

Summary of opportunity:

We are seeking a candidate to undertake an exciting PhD project in the field of fungal biology, focussing on the use of hyphal fusion processes to support the use of fungal mycelium as a sustainable fabrication material. This Australian Research Council-funded project forms part of a broader interdisciplinary research program working on myco-materials. The successful candidate will be an analytical, intellectually curious researcher with a background in biochemistry or molecular biology, preferably with experience working with basidiomycete fungi. They will work alongside experts in sustainable fabrication, the use of myco-materials, and circular design methods.

The project will investigate and optimise mycelial growth conditions that maximize the hyphal fusion processes required for bonding components of mycelial design components. This builds on our previous research on the growth of Ganoderma and Pleurotus mycelium (reishi and oyster mushrooms, respectively)[1], which has demonstrated that blocks of mycelium form strong bonds with each other under appropriate conditions, due to the process of hyphal fusion (anastomosis). The project will use a proteomics approach to investigate hyphal fusion process in Australian endemic isolates of Pleurotus ostreatus and Ganoderma steyaertanum, in collaboration with the Proteomics Core Facility at the University of Sydney. This aims to identify and characterise the key proteins involved in cell wall modification and hyphal remodelling during hyphal fusion in these species, and to compare these findings with existing data from the button mushroom (Agaricus bisporus)[2].

Insights from this work will support the development of novel methods and reagents for targeted stimulation of hyphal fusion within mycelium based design components. These innovations will enable applications such as self healing materials, structural bridging between components, and biologically driven gap filling processes.

This Scholarship is funded by the Australian Research Council (ARC) and aims to support a PhD candidate undertaking research within the School of Life and Environmental Sciences, Faculty of Science, at the University of Sydney.

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