Fungal and Enzyme Biotechnology

Production of proteins, lipids and biochemicals by filamentous fungi

Associate Professor Robert Speight at the Mackay Renewable Biocommodities Pilot Plant

Filamentous fungi have wide applications in the production of food and food additives (soy source, fermented soybeans, etc.), organic acids (citric acid, lactic acid, etc.), lipids and enzymes. Lipids, depending on their composition, can be used as substrates for the production of functional foods, nutraceuticals, or biodiesel. In recent years, lipid production by filamentous fungi has received increasing interest. The major advantages of lipid production by filamentous fungi include high productivity, low nutrient requirements, ability to metabolise C5 sugars, and simple biomass harvest by filtration. QUT has considerable experience working with a range of fungal lipid producers and is currently working on process optimisation and scale-up.

In particular T. reesei is an industrial workhorse filamentous fungus for the production and secretion of its own hydrolytic enzymes for the hydrolysis of different biomass feedstocks down to fermentable C6/C5 sugars. T. reesei can also be developed to be high producer and secretor of recombinant gene products such as thermophilic enzymes suitable for the complete hydrolysis of different biomass feedstocks used in different applications such as biofuels, oil and gas. QUT has extensive experience in designing and creating recombinant strains of T. reesei which undergoes further strain optimisation through genetic and cultivation improvement processes resulting in the high-level production of different bioproducts targeted for secretion into the cultivation medium, easing downstream processing. Futhermore, QUT has experience in scaling up T. reesei fermentation to commercial scale.

Functional enzyme characterisation

The screening of biodiversity and identification of novel gene sequences through genomics and transcriptomics generates a large number of putative enzymes with unknown function. We are developing a bioinformatics approach to pre-select sequences identified from biodiversity screening or from the genomic databases. This approach is based on sequence homology to sequences of known function and characteristics as well as both public and novel approaches to estimate protein stability. To maximise the numbers of enzymes that can be functionally tested, we are using a cell-free expression platform to rapidly integrate genes (as PCR products) from biodiversity screening or synthetic DNA from database screening to produce enzymes for testing in miniaturised micro-titre plate based functional assays. QUT has extensive experience in development and implementation of medium to high-throughput assays for quantitation of enzyme activity and physicochemical characterisation, with a particular focus on enzymes that modify cellulose, hemicellulose, and lignin.

Our projects