Resubmission novel bionanocatalysts and nanomagnets from solutions and metal bearing wastes

Lead Research Organisation: University of Manchester
Department Name: Earth Atmospheric and Env Sciences

Abstract

The property of matter changes at the nanoscale, because atoms at the surface of a crystal have different properties from those buried within it. Nanocrystals have a large proportion of surface atoms so these revealed properties could be utilised, including enhanced catalytic/magnetic properties. However they are unstable during manufacture and are difficult to make because they want to agglomerate. When this happens their properties are lost. Agglomeration can be prevented by using molecular 'cradles'. This is difficult and expensive: the cradle must shield each nanoparticle from its neighbours, but allow some area to remain exposed. Bacterial surfaces provide good cradles. Metallic nanoparticles are made by bacterial enzyme action, and cradling by local biomolecules as they grow, individually, on bacterial surfaces. Examples are precious metals (PMs: Pd,Pt,Au) and iron (oxides). PMs are reduced by bacteria to the metallic state. Fe oxides exist in various mineral forms which are made and chosen via combinations of bacterial action, and chemical reactions in the bacterially-influenced 'reaction space'. The net results are supported catalysts & magnets with special properties attributable to their nanosize. Traditionally PMs make good chemical catalysts, and Fe-oxides make good magnets, but at the nanoscale these distinctions blur: palladium is ferromagnetic while Fe oxides have catalytic activity. Even better, hybrid PM/Fe nanoparticles are BETTER in both applications than single metals but nobody has attempted to bio-direct the synthesis of hybrid nanoparticles (called bimetallic or trimetallic clusters). The instability of nanoparticles makes this very difficult indeed using chemistry. Bacteria can make mixed metal nanoparticles from mixed solutions and they can even do this by scavenging the metals from liquid wastes. Indeed, some bacteria-bound trimetallics were found to have better catalytic properties than mono- nanocrystals. This may be due to the intruding metal forcing changes in the crystal structure so that 'buried' atoms are persuaded to think that they are more like surface ones. Similar changes could also be brought about by application of electromagnetic fields (EMF; dielectric processing) during and following crystal synthesis but this has not been tried before. A combination of stable nanoparticles on bacteria plus dielectric processing could make a new generation of supernanoparticles, far in advance of what we already have. We aim to define the potential for making completely new materials using a portfolio of our bacteria as the catalysts for nanoparticle synthesis, and support. Some bacteria reduce PMs, some make ferric oxides, some do both. We will biomanufacture nanoscale chemical catalysts (PMs), nanomagnets (Fe), swop to get PM-magnets and Fe-catalysts and then combine them to make novel PM/Fe hybrids. We will relate what we make to how we make it, i.e the bacterial activity/surface properties and the crystals made. The industrial Partner will dielectric-process the bionanoparticles to further enhance their properties and a collaboration with Cardiff will use electron microscopy to be able to see what we have made, down to the atomic level. We will do example catalytic and magnetic testing of the bionanomaterials in the Universities against commercial standard materials. Mainly we will use pure metal solutions and bacterial strains for fundamental study. Finally, with the best bacteria, we will briefly look at example novel bionanomaterials made from mining wastes (Fe) and industrial wastes (Pd/Au) since we know these can work even better. We will use multifunctional bacteria and also some enhanced by mutations as appropriate

Technical Summary

We will test the hypothesis that bionanomanufacturing makes novel nanomaterials that chemistry cannot; nanoparticles have unique properties but chemically supporting them to prevent agglomeration, & bulk synthesis are difficult/expensive. Bacterial surfaces are used to pattern, template & support stable metal nanocluster deposition & nanoparticle growth, promoted & controlled enzymatically.1. We will explore feasibility to make bionanocatalysts/ nanomagnets in 3 examples: (i) precious metal (PM) & Fe-based bionanocatalysts; (ii) PM/Fe based bionanomagnets; (iii) bacteria which deposit both PMs + Fe, directed to hybrid & bimetallic cluster biosynthesis, a major challenge conventionally. 2. We will establish biogrowth & processing methods for optical particle size/dispersion for potential applications. 3. We will apply dielectric processing to extant bionanocrystals & during the biogrowth process, determining optimal conditions for stability & activity. 4. We will look at crystal structures (using solid state & synchrotron-methods: EXAFS, XANES). magnetic (SQUID, XMCD) and surface phenomena (high resolution atomic level TEM/AFM to map crystal surface defects, kinks & terraces where reactions happen), relating structure to function, to help establish WHY BIOnanocrystals can have better activity than their chemical counterparts. Contrary to common perception nano-Fe(III) is catalytic and nano-Pd(0) is ferromagnetic. We will explore these potential multifunctionalities, uniting magnetic & catalytic phenomena within electron spin concepts, regarding the bionanocrystals as inorganic overlayers ('molecular amplifiers') of enzymatic systems, developing a strategy for future applications-targeted nanomaterials fabrication: a 'virtual shop' of niche products based on a microbial portfolio developed and tested within the study. Last, we will briefly examine biorecovery of active PMs/Fe from wastes, addressing dual 'global' problems of waste disposal & resource efficiency.

Publications

10 25 50

publication icon
Cutting RS (2010) Optimizing Cr(VI) and Tc(VII) remediation through nanoscale biomineral engineering. in Environmental science & technology

publication icon
Cutting RS (2012) Microbial reduction of arsenic-doped schwertmannite by Geobacter sulfurreducens. in Environmental science & technology

publication icon
Lloyd JR (2011) Biotechnological synthesis of functional nanomaterials. in Current opinion in biotechnology

 
Description We were successful in making a range of completely new materials using a portfolio of bacteria as the catalysts for nanoparticle synthesis. As proposed, we developed novel biomanufacturing procedures to make nanoscale chemical catalysts (PMs), nanomagnets (Fe), swapped to get PM-magnets and Fe-catalysts and then combined them to make novel PM/Fe hybrids, which we showed functioned as magnetically recoverable catalysts for a synthesis and remediation. The underlying physiology of the biomanufacturing processes were studied, and in the case of the Fe-based materials studied in Manchester, we were able to define a range of parameters that controlled the size, structure and activity of the magnetite-based materials. With our industrial partner (C-Tech Innovation) we were also able to show that the reactivity of the materials could be manipulated by controlling a magnetic field applied to the cultures during biomagnetite synthesis. By varying the parameters highlighted were able to optimise the production of nano-scale functionalised biomagnetite for hyperthermic cancer treatment, heck coupling synthetic reactions and the bioremediation of toxic organic and inorganic species. In all cases, state of the art spectroscopy and imaging techniques were used to characterise the functional materials at an atomic scale. Waste Fe(III) minerals from acid mine drainage and water treatment/polishing were not converted to biomagnetite, but did yield Fe(II)-bearing minerals suitable for bioremediation applications. The results from our studies were published in the top journals in the field and we have been commissioned to write reviews on this new area of bionanotechnology e.g. for Current Opinion in Biotechnology .

Specific outputs include:
1. The development of cost effective, scalable novel patented bioproduction methods for the green synthesis of wide range of microbial nanomagnets. Biomagnetite materials were developed for enhanced catalytic activity against metals (Environmental Science and Technology 2010 44 2577-2584) and organics (manuscript in preparation) through optimisation of the starting Fe(III) mineral and physiological manipulations. Additional doping regimes, using transition metals, were used to enhancedmagnetic properties e.g. coercivity for magnetic applications including hyperthermic cancer treatment (ACS Nano 2010 3 1922-1928).

2. Patented methods were also developed for coating bionanomagnetite with PMs including catalytically-active Pd nanoparticles for organic synthesis (ACS Nano 2009 4 2577-2584) and recalcitrant toxic chlorinated organics e.g. TCE (International Biodeterioration & Biodegradation. DOI: 10.1016/j.ibiod.2016.12.008).

3. The development of infrastructure and methodologies required to access state of the art spectroscopy techniques using overseas facilities e.g. Canadian, Swiss and US (Berkeley) synchrotrons, for future use by the international and UK user community e.g. for XMCD and STXM at the Diamond synchrotron.
Exploitation Route Follow-on work was supported by (1) a BBSRC CASE studentship, (2) EPSRC KT grant focuses on the scale-up of production of bionanomagnetite optimised for in situ and ex situ remediation applications with Parsons Brinkerhoff and the Centre for Process Innovation and (3) a major EU grant, Nanorem.
Sectors Chemicals,Digital/Communication/Information Technologies (including Software),Electronics,Energy,Environment,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology

 
Description Materials from this grant are being assessed for use in remediation applications for metals, organics and radionuclides with commercial partners. Other links are being developed for catalysis and medical applications.
First Year Of Impact 2009
Sector Chemicals,Environment,Manufacturing, including Industrial Biotechology
Impact Types Economic