David Ralph  from Murdoch University in Perth Australia.

Contact me


9360 2887



Fellow researchers

    Latest news

    • Research
    • School

    Dr David Ralph
    B.Sc. (Hons) Ph.D. (Murdoch)

    Senior Lecturer

    Teaching area

    My teaching duties are currently spread over the three undergraduate years.  In first year I lecture in Foundations of Chemistry (CHE144) and tutor in the Open University SCI18 uni.   I coordinate and lecture the second year unit Physical Chemistry 1 (CHE202)  and present lectures on kinetics in the unit Engineering Kinetics (ENG255).   I also lecture a section in third year focusing on the chemistry and biochemistry of metabolic processes.

    Research areas

    Early research interests included the chemistry of natural products.  My doctoral studies changed the emphasis somewhat and I became interested in waste treatment and the recycling of the ‘nutrient elements’ carbon, nitorgen and phosphorous.  The foundations  of waste treatment and recycling are the anabolic and catabolic activities  of micro-organisms and I soon learned the fact that these little ‘microbes’ run the whole system that we live and depend upon. Since discovering the lithotrophic lifestyle in the early 1990′s, ie. cells that are the ‘rock-eaters’, most of my research has been focussed on their activities and what controls those activities.

    Current projects

    The current focus of my research projects is the use of microbes in the area of hydrometallurgy.  Hydrometallurgy is the use of water and solution chemistry to separate and purify metals from their host minerals or ores.  It often generates surprise when this is explained because the common view of metallurgy is that of the forge and the furnace.  However microbes have a very significant geochemical role in the natural envinronment, catalysing the oxidation of sulfidic minerals at the earth’s surface as well as the oxidation of dissolved metals such as iron and manganese. 

    Chemolithotrophic organisms are among the first colonisers of sterile or disturbed soils since they require no reduced carbon to commence and manitain their growth.  With this ability they become the important first step in the transformation of minerals back into soil material.  This class of microbes are the foundation of many eco-systems which can develop from stored chemical energey rather than sunlight.  The ecosystems surrounding thermal vents in the deep ocean are an example of these extreme habitats.




    • Minakshi Sundaram, M., Ralph, D., Singh, P., Yin, C., (2014), New Insights into the Electrochemical Behavior of Hematite (alpha-Fe2O3) Microparticles in Strong Aqueous Basic Electrolyte: Formation of Metallic Iron, Metallurgical and Materials Transactions A - Physical Metallurgy and Materials Science, 45A, 4, pages 2023 - 2029.
    • Mullett, M., Fornarelli, R., Ralph, D., (2014), Nanofiltration of mine water: Impact of feed pH and membrane charge on resource recovery and water discharge, Membranes, 4, 2, pages 163 - 180.
    • Shiers, D., Ralph, D., Watling, H., (2014), The effects of nitrate on substrate utilisation by some iron(II)- and sulfur-oxidising Bacteria and Archaea, Hydrometallurgy, 150, , pages 259 - 268.
    • Minakshi Sundaram, M., Ralph, D., (2013), A Novel Sodium-Ion Rechargeable Battery, ECS Transactions, 45, 29, pages 95 - 102.
    • Shiers, D., Ralph, D., Bryan, C., Watling, H., (2013), Substrate utilisation by Acidianus brierleyi, Metallosphaera hakonensis and Sulfolobus metallicus in mixed ferrous ion and tetrathionate growth media, Minerals Engineering, 48, , pages 86 - 93.
    • Blight, K., Candy, R., Menzel, M., Ralph, D., (2012), Total dissolved solids and their effects on iron oxidation by chemolithotrophic cells, Hydrometallurgy, 125, 0, pages 109 - 114.
    • Minakshi Sundaram, M., Singh, P., Ralph, D., Appadoo, D., Blackford, M., Ionescu, M., (2012), Structural characteristics of olivine Li(Mg0.5Ni0.5)PO4 via TEM analysis, Ionics: international journal of ionics, 18, 6, pages 583 - 590.
    • Minakshi Sundaram, M., Sharma, N., Ralph, D., Appadoo, D., Nallathamby, K., (2011), Synthesis and Characterization of Li(Co0.5Ni0.5)PO4 Cathode for Li-Ion Aqueous Battery Applications, Electrochemical and Solid-State Letters, 14, 6, pages A86 - A89.
    • Shiers, D., Ralph, D., Watling, H., (2011), Batch culture of Acidithiobacillus caldus on tetrathionate, Biochemical Engineering Journal, 54, 3, pages 185 - 191.
    • Yin, C., Minakshi Sundaram, M., Ralph, D., Jiang, Z., Xie, Z., Guo, H., (2011), Hydrothermal synthesis of cubic alpha-Fe2O3 microparticles using glycine: Surface characterization, reaction mechanism and electrochemical activity, Journal of Alloys and Compounds, 509, 41, pages 9821 - 9825.
    • Watling, H., Watkin, E., Ralph, D., (2010), The resilience and versatility of acidophiles that contribute to the bio-assisted extraction of metals from mineral sulphides, Environmental Technology, 31, 8-9, pages 915 - 933.
    • Shiers, D., Ralph, D., Watling, H., (2010), A comparative study of substrate utilisation by Sulfobacillus species in mixed ferrous ion and tetrathionate growth medium, Hydrometallurgy, 104, 3-4, pages 363 - 369.
    • Mishra, D., Ahn, J., Kim, D., Chaudhury, G., Ralph, D., (2009), Dissolution kinetics of spent petroleum catalyst using sulfur oxidising acidophilic microorganisms, Journal of Hazardous Materials, 167, , pages 1231 - 1236.
    • Kim, D., Mishra, D., Ahn, J., Chaudhury, G., Ralph, D., (2009), A novel process to treat spent petroleum catalyst using sulfur-oxidsing lithotrophs, Journal of Environmental Science and Health. Part A: Toxic Hazardous Substances and Environmental Engineering, 44, 14, pages 1585 - 1591.
    • Blight, K., Candy, R., Ralph, D., (2009), The preferential oxidation of orthorhombic sulfur during batch culture, Hydrometallurgy, 99, 2009, pages 100 - 104.
    • Candy, R., Blight, K., Ralph, D., (2009), Specific iron oxidation and cell growth rates of bacteria in batch culture, Hydrometallurgy, 98, 2009, pages 148 - 155.
    • Kim, D., Mishra, D., Park, K., Ahn, J., Ralph, D., (2008), Metal Leaching from Spent Petroleum Catalyst by Acidophilic Bacteria in Presence of Pyrite, Materials Transactions, 49, 10, pages 2383 - 2388.
    • Mishra, D., Kim, D., Ralph, D., Ahn, J., Rhee, Y., (2008), Bioleaching of metals from spent lithium ion secondary batteries using Acidithiobacillus ferrooxidans, Waste Management, 28, 2, pages 333 - 338.
    • Mishra, D., Kim, D., Ralph, D., Ahn, J., Rhee, Y., (2008), Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect, Journal of Hazardous Materials, 152, , pages 1082 - 1091.
    • Blight, K., Ralph, D., (2008), Maximum yield and standard enthalpy of iron-oxidising bacteria, Hydrometallurgy, 93, , pages 66 - 71.
    • Blight, K., Ralph, D., (2008), Aluminium sulphate and potassium nitrate effects on batch culture ofiron oxidising bacteria, Hydrometallurgy, 92, 3-4, pages 130 - 134.
    • Mishra, D., Kim, D., Ralph, D., Ahn, J., Rhee, Y., (2007), Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetic aspect, Journal of Hazardous Materials, TBA, , pages TBA - TBA.
    • Mishra, D., Kim, D., Ralph, D., Ahn, J., Rhee, Y., (2007), Bioleaching of vanadium rich spent refinery catalysts using sulfur oxidizing lithotrophs, Hydrometallurgy, 88, , pages 202 - 209.
    • Shiers, D., Blight, K., Ralph, D., (2005), Sodium sulphate and sodium chloride effects on batch culture of iron oxidising bacteria, Hydrometallurgy, 80, , pages 75 - 82.
    • Blight, K., Ralph, D., (2004), Effect of ionic strength on iron oxidation with batch cultures of chemolithotrophic bacteria, Hydrometallurgy, 73, , pages 325 - 334.
    • Blight, K., Ralph, D., Thurgate, S., (2000), Pyrite Surfaces after Bio-leaching: A Mechanism for Bio-oxidation, Hydrometallurgy, 58, , pages 227 - 237.
    • Blight, K., Ralph, D., (1999), Microbes and Hydrometallurgy, Chemistry in Australia, 66, , pages 11 - 12.
    • May, N., Ralph, D., Hansford, G., (1997), Dynamic Redox Potential Measurement for Determining the Ferric Leach Kinetics of Pyrite, Minerals Engineering, 10, , pages 1279 - 1290.


    • Shiers, D., Ralph, D., Watling, H., (2011),The effect of KNO3 on substrate utilisation by Sulfobacllius sp. in mixed ferrous ion and tetrathionate growth medium.,In: 19th International Biohydrometallurgy Symposium (IBS) (2011).
    • Minakshi Sundaram, M., Ralph, D., Blackford, M., Ionescu, M., (2011),LiNiPO4 Aqueous Rechargeable Battery,In: 219th ECS Meeting.
    • Shiers, D., Ralph, D., Hatling, H., (2009),Substrate utilisation by Sulfobacillus thermosulfidooxidans in mixed ferrous ion and tetrathionate growth medium,In: 18th International Biohydrometallurgy Symposium (IBS) (2009).