Ecological impacts of biological and chemical surfactants on aquatic biofilm growth metabolism and carbon cycling (EcoSurf)

Summary

Surfactants are chemicals that adsorb at the interface of a liquids, allowing it to foam or penetrate a solid. Surfactants such as sodium lauryl sulphate have a range of domestic and industrial applications, such as detergents. Consequently, surfactants represent a significant component of human wastewater, yet their removal by wastewater treatment plants is inefficient. In inland waters, microbial life is dominated by biofilms attached to surfaces and aggregates (“river snow”) suspended in the water column1.

Both are composed of microbial cells embedded within an extracellular polysaccharide (EPS) matrix. Biofilms and aggregates exist on a continuum, with aggregates formed through the erosion of streambed biofilms1, whilst biofilms trap aggregates regulating, their transport downstream2,3. Biofilm dwelling microorganisms produce biosurfactants, such as rhamnolipid and sophorolipids, to alter biofilm structure and permeability. Biosurfactants, thus, control a biofilm’s resistance to erosion, its ability to trap and retain particles and capacity for dissolved gas and nutrient exchange.

There is growing interest from the chemical industry regarding the potential of biosurfactants to provide environmentally friendly alternatives to chemical detergents. Biosurfactants are capable of being biologically degraded, and tend to have lower toxicity to aquatic fauna4. In addition, given their capacity to influence biofilm structure, biosurfactants exhibit potential as antifouling treatments for boat hulls and submerged structures5.

To accurately assess their potential benefits as industrial and domestic detergents, however, we must test how biosurfactants affect the structure and functioning of complex aquatic biofilms.

The EcoSurf project will seek to elucidate how chemical and biological surfactants affect

i)the formation and structure of streambed biofilms,

ii)interactions between streambed biofilms and suspended microbial aggregates within streamwater

iii)biofilm metabolism and carbon cycling.

This requires a multidisciplinary approach combining methods from aquatic ecology, eco-hydrology, microbial ecology and molecular biology. This requires a multidisciplinary approach combining methods from aquatic ecology, eco-hydrology, microbial ecology and molecular biology.

The student will be supervised by Dr Billy Hunter, from the School of Geography and Environmental Science who has specific expertise in investigating the impacts of environmental change upon aquatic biofilms; Professor Ibrahim Banat in the School of Biomedical Sciences, who has specific expertise in the production of microbial biosurfactants’ and their biotechnological and industrial application; and Dr Joerg Arnscheidt, a Senior Lecturer in Earth Systems Science from the School of Geography and Environmental Science with expertise in water quality monitoring and aquatic ecology.

The project will also include international collaboration with Dr Jakob Schelker at the University of Vienna’s Department of Limnology and Bio-Oceanography, University of Vienna.

Through this collaboration, the student will have access to the internationally excellent experimental mesocosm facilities at the Austrian Interuniversity Centre for Aquatic Ecosystem Research (WCL http://www.wasserkluster-lunz.ac.at) which is a globally recognised centre of excellence for water research. The WCL has supported research leading to over 200 publications in leading journals (including Nature; Nature Geoscience; ISME Journal; and the Proceedings of the National Academy of Sciences) over the past 10 years and is the partner in the pan-European Aquacosm network of environmental research facilities (www.aquacosm.eu).

References

¹Battin et al. (2003). Nature, 426: 439–442

²Hunter et al. (2016). Geophys. Res. Lett., 43, doi:10.1002/2016GL067719.

³Roche et al. (2017). Water Resour. Res., 53, doi:10.1002/2016WR019041.

⁴Banat et al.(2014). Applied Microbiology and Biotechnology, 98: 9915–9929. DOI: 10.1007/s00253-014-6169-6.

⁵Chebbi et al. (2017). Journal of Basic Microbiology  9999:1-12.  DOI 10.1002/jobm.201600658.

Essential criteria

• To hold, or expect to achieve by 15 August, an Upper Second Class Honours (2:1) Degree or equivalent from a UK institution (or overseas award deemed to be equivalent via UK NARIC) in a related or cognate field.

• A comprehensive and articulate personal statement

Desirable Criteria

If the University receives a large number of applicants for the project, the following desirable criteria may be applied to shortlist applicants for interview.

• First Class Honours (1st) Degree
• Masters at 65%
• Research project completion within taught Masters degree or MRES
• Experience using research methods or other approaches relevant to the subject domain
• Work experience relevant to the proposed project
• Experience of presentation of research findings

Funding

The University offers the following awards to support PhD study and applications are invited from UK, EU and overseas for the following levels of support:

Vice Chancellors Research Studentship (VCRS)

Full award (full-time PhD fees + DfE level of maintenance grant + RTSG for 3 years).

This scholarship will cover full-time PhD tuition fees and provide the recipient with £15,000 maintenance grant per annum for three years (subject to satisfactory academic performance). This scholarship also comes with £900 per annum for three years as a research training support grant (RTSG) allocation to help support the PhD researcher.

Vice-Chancellor’s Research Bursary (VCRB)

Part award (full-time PhD fees + 50% DfE level of maintenance grant + RTSG for 3 years).

This scholarship will cover full-time PhD tuition fees and provide the recipient with £7,500 maintenance grant per annum for three years (subject to satisfactory academic performance). This scholarship also comes with £900 per annum for three years as a research training support grant (RTSG) allocation to help support the PhD researcher.

Vice-Chancellor’s Research Fees Bursary (VCRFB)

Fees only award (PhD fees + RTSG for 3 years).

This scholarship will cover full-time PhD tuition fees for three years (subject to satisfactory academic performance). This scholarship also comes with £900 per annum for three years as a research training support grant (RTSG) allocation to help support the PhD researcher.

Department for the Economy (DFE)

The scholarship will cover tuition fees at the Home rate and a maintenance allowance of £15,285 per annum for three years. EU applicants will only be eligible for the fee’s component of the studentship (no maintenance award is provided). For Non-EU nationals the candidate must be "settled" in the UK. This scholarship also comes with £900 per annum for three years as a research training support grant (RTSG) allocation to help support the PhD researcher.

Due consideration should be given to financing your studies; for further information on cost of living etc. please refer to: www.ulster.ac.uk/doctoralcollege/postgraduate-research/fees-and-funding/financing-your-studies