Biotechnological exploitation of gut microorganisms and lignocellulosic substrates

A novel area of research has been examining the microbial activity within the digestive tract of ruminants and hind-gut fermenting mammals. The microbial consortia in these ecosystems can effectively ferment carbon-containing polymers in lignocellulosic biomass, producing volatile fatty acids and microbial proteins to ‘feed’ the animal. Two members of the digestive tract consortium, the anaerobic fungi and their associated methanogenic partners, are of particular interest in this regard. By using scaffolding-like structures on their cell-surfaces to which the correct cellulolytic enzymes are tethered both temporally and spatially, the anaerobic fungi are unique in the microbial kingdoms in their ability to rapidly and effectively degrade lignocellulosic substrates.

 In digestive systems that harbour these fungi, they exist alongside methanogens which are identical to those found in anaerobic digestion (AD) systems and result in the production of methane by ruminants. While the digestive tract of ruminants and large mammalian herbivores can support anaerobic fungal populations, they are not found in conventional AD systems.

From a biotechnology perspective, using anaerobic fungal cultures with/without methanogens to degrade lignocellulosic biomass (e.g., energy crops, crop residues) and farm-yard residues that contain lignocellulosic constituents (e.g., poultry litter, farm-yard manures (FYM)) would dramatically increase the potential feedstocks that could be used for biofuel generation. When cultured on their own, anaerobic fungi could convert lignocellulosic substrates to hydrogen, ethanol and acetic acid, producing biofuels and platform chemicals, and carbon dioxide for use within the food supply chain. When grown in co-culture with methanogens, the conversion process would result in the production of biogas (methane and carbon dioxide).

Research aim and objectives

Previous research has demonstrated that anaerobic fungi and methanogens can be isolated from the digestive tract and grown in the laboratory on a broad range of lignocellulosic substrates. Recent work from a Harper Adams collaboration with the University of York has shown that these co-cultures can be grown on wheat straw in the presence of FYM (10% v/v) at laboratory-scale. This PhD program would extend these exciting recent studies to examine the biology and exploitability of these observations in considerably more detail. The aim of the research is to determine the potential of using anaerobic fungi with/without methanogens to degrade lignocellulosic substates in a process similar to the AD process. The research has two main objectives as follows:

1. Determine the ability of anaerobic fungi with/without methanogens to degrade lignocellulosic substrates in a novel AD-like process that includes FYM/slurry as a component of the culture system.

2. Quantify the potential biofuel/platform chemical generation from the fungus/fungal co-culture consortium.

Successful candidates will receive a yearly stipend (paid monthly) for maintenance set at the UKRI rate – for 2024/5 this will be £19,237. The scholarship will cover tuition fees for ‘home’ students (UK and Republic of Ireland). Harper Adams University is unfortunately unable to offer a tuition fee waiver for international students applying and evidence of funding will be required for International Fee paying students to show they can cover the difference between the UK and international fees for the full four years – for the 2024/5 academic year this amount is £10,890. However, scholarships maybe be available at the time of appointment to cover the difference between UK and International fees for the duration of the programme.

Suitable applicants will have a background in microbiology, a specific interest in microbial ecology and fermentation technology and have a willingness to embrace the opportunity to gain experience in a range of unique scientific techniques for working with anaerobic microbial fermentation systems. In return, you will be provided with guidance and supervision from experts in the relevant disciplines, based at Harper Adams University and from part of a wider collaboration with international partners around the world, to guide you through your PhD studies. Applicants must hold a minimum of a 2:1 or equivalent bachelor’s degree in an appropriate subject/high grade point average bachelor’s degree for international applicants or a 2.2 alongside a suitable Master’s Degree. Potential for research based on alternative qualifications/experience as judged acceptable by the university, will be considered on a case-by-case basis.

Please direct any queries related to the PhD project to Dr Marie Kirby ([email protected]).