Current ERG Research
Mr. Adil Bakir
'Development of a biosorption column utilising seaweed-based biosorbents for the removal of metals from industrial waste streams'
In accordance with the framework set out in the EU Directive 2006/11/EC (on pollution caused by certain dangerous substances discharged into the aquatic environment of the Community), industries in Member States are required to find environmentally acceptable ways to reduce their wastewater metal (List II substances) content before release into waterways. The use of seaweed biomass for this purpose has advantages over conventional chemical and biological means. Seaweeds are widely available, inexpensive and have a potentially high metal sorption capacity. These properties, combined with the environmental benefits of utilising a renewable resource, make seaweed biomass an attractive wastewater treatment alternative.
The objective of this work is to develop and test a laboratory prototype fixed-bed sorption column system, using seaweed biomass, for a variety of toxic metal species (Zn2+, Ni2+, Al3+ and Sb3+). Optimisation of the main physico-chemical factors, such as regeneration cycles, desorption, and selective recovery of metals when present in multi-component waste streams, will be performed. The removal of metal ions in a seaweed fixed-bed biosorption column proceeds chiefly through an ion-exchange mechanism (carboxyl, hydroxyl and sulphonate groups on the seaweed biomass). Mathematical models (COMSOL) are being developed and optimised in order to simulate metal sorption mechanics and to predict breakthrough concentrations.
Ms. Catherine Murphy
'A study of factors affecting biosorption of chromium by a variety of seaweed species'
This project studies the accumulation of chromium by species of seaweeds common to South-east Ireland in order to identify those seaweeds with a high capacity for bioaccumulation and to investigate the mechanisms of bioaccumulation. Seaweed has the ability to concentrate relatively high amounts of metal in its tissues in both live and dead form. Bioaccumulation occurs in live seaweeds and is an active process where the metal is metabolised by the seaweed.
Heavy metals in the aqueous environment are of particular concern because of their ability to bioaccumulate in the food chain, making it possible for toxic levels to reach higher animals and plants. Chromium occurs predominantly in Cr(III) and Cr(VI) oxidation states. It is used in steel manufacturing, the production of ferrous and non-ferrous alloys, electroplating, leather tanning and in the production of pigments. Cr(VI) compounds are in general more soluble, mobile and more bioavailable than Cr(III) compounds.
Chromium uptake is studied by acid digestion and ICP-OES analysis of seaweed that has been exposed to elevated concentrations of metal over varying timeframes and temperatures. FTIR spectroscopy is used to identify the key functional groups present on the seaweed surface and their relative importance in the metal binding process. Scanning Force Microscopy (SFM) is used to observe changes which occur on the seaweed surface during metal uptake - Significant impacts on surface topography have been observed.
Mr. David O’Neill
'Investigation into the genomic/proteomic effects of metal contamination in seaweed'
This study primarily examines the rhodophyte (red seaweed) Polysiphonia lanosa and aims to isolate a range of genes whose expression is regulated by metals. Further objectives include the isolation and characterisation of resultant proteins and the examination of whether they possess metal-binding capabilities. The seaweed genes, whose expression is metal regulated, have been isolated from a subtracted cDNA library in a previous study carried out at the ERG, WIT. Relative quantitative real-time PCR is used to determine the expression levels of these induced genes following P. lanosa’s exposure to various metals. The study also aims to construct a genomic library for P. lanosa and to then screen to investigate the possible existence of gene-encoded Class I and Class II metallothionein genes, along with other genes responsible for the production of stress-induced proteins.
Another aspect of this project relates to the bacterial community present on the seaweed surface. Our aim is to determine if bacterial strains isolated from the surface of a number of seaweed species have the ability to accumulate and tolerate elevated levels of heavy metals in polluted waters, and to determine if these marine bacteria, identified by molecular methodologies, contribute to the seaweed’s own ability to accumulate and detoxify metals from the marine environment.
Ms. Siobhan Ryan
'Investigation into the biochemical effects of metal contamination in seaweeds'
Heavy metal pollution is a worldwide environmental problem. Over the past two decades much attention has been focused on identifying materials that are capable of effectively removing heavy metals from aqueous environments. Among the biomaterials studied, seaweeds (macroalgae) were found to be extremely efficient. Seaweeds possess cellular proteins, which bind the metals and store them in compartments within the cell or exclude them to the surrounding environment. These metal binding proteins are believed to be phytochelatins, low molecular weight, cysteine-rich polypeptides that complex ‘soft’ metal ions in thiol clusters. Phytochelatins possess the general structure (g-Glu-Cys)n-X, where X is Gly, g-Ala, Ser or Glu and n = 2-11.
In-vitro and in-vivo studies with plants on the metal-dependent synthesis of phytochelatins suggest that metal ions are probably the primary activators of phytochelatin synthase. Our studies will investigate if the same is true for phytochelatins from algal sources.
In addition, there is a widespread distribution of sulfated polyphenols in brown and red algae, which chelate to a variety of heavy metal ions. This study will isolate and purify proteins and polyphenols from a variety of algae and examine their metal binding properties. The impact of increasing metal levels on the concentration of proteins and polyphenols in-vivo will also be investigated.
SEAFEED Biodiscovery Programme
'Unlocking the Bioactive Potential of Seaweed for Novel Animal Health Applications'
The ERG SEAFEED initiative currently supports one postdoctoral (Dr. Laurie O'Sulivan) and two postgraduate (Ms. Tan Shiau Pin & Ms. Mari Luz Prieto) researchers. The ‘SEAFEED’ biodiscovery programme will mine seaweed for antimicrobial, anti-infective and prebiotic activity and validate the safety and efficacy of the most promising extracts/bio-molecules in pig-feeding trials. The aim is to develop scientifically-validated bioactive feed additives from sustainable seaweed sources with the potential to achieve the health and performance targets necessary for cost-effective production in the absence of in-feed antibiotics. This research will therefore enhance competitiveness and sustainability of the agri-food and marine sectors. Our long-term strategy is to create an R&D platform to enhance future development opportunities for the EIRC, in areas such as food, biomedical and pharmaceuticals.
Past ERG Projects
Dr. Vanessa Murphy (2007)
'An investigation into the mechanisms of heavy metal binding by selected seaweed species'
Dr. Richard Walsh (2008)
'Development of a biosorption column utilising seaweed-based biosorbents for the removal of metals from industrial waste streams'
Dr. James Cusack (2008)
'Isolation of genes associated with metal accumulation in seaweeds'
Taking seaweed samples from the intertidal zone