Bacterial recovery and recycling of tellurium from tellurium-containing compounds by Pseudoalteromonas sp. EPR3

Aims: Tellurium-based devices, such as photovoltaic (PV) modules and thermoelectric generators, are expected to play an increasing role in renewable energy technologies. Tellurium, however, is one of the scarcest elements in the earth's crust, and current production and recycling methods are inefficient and use toxic chemicals. This study demonstrates an alternative, bacterially mediated tellurium recovery process. Methods and Results: We show that the hydrothermal vent microbe Pseudoalteromonas sp. strain EPR3 can convert tellurium from a wide variety of compounds, industrial sources and devices into metallic tellurium and a gaseous tellurium species. These compounds include metallic tellurium (Te0), tellurite (TeO32−), copper autoclave slime, tellurium dioxide (TeO2), tellurium-based PV material (cadmium telluride, CdTe) and tellurium-based thermoelectric material (bismuth telluride, Bi2Te3). Experimentally, this was achieved by incubating these tellurium sources with the EPR3 in both solid and liquid media. Conclusions: Despite the fact that many of these tellurium compounds are considered insoluble in aqueous solution, they can nonetheless be transformed by EPR3, suggesting the existence of a steady state soluble tellurium concentration during tellurium transformation. Significance and Impact of the Study These experiments provide insights into the processes of tellurium precipitation and volatilization by bacteria, and their implications on tellurium production and recycling.Engineering and Applied Science

Phase locking in quantum and classical oscillators: polariton condensates, lasers, and arrays of Josephson junctions

We connect three phenomena in which a coherent electromagnetic field could be generated: polariton condensation, phase-locking in arrays of underdamped Josephson junctions, and lasing. All these phenomena have been described using Dicke-type models of spins coupled to a single photon mode. These descriptions may be distinguished by whether the spins are quantum or classical, and whether they are strongly or weakly damped.Comment: 6 pages, RevTex. To appear in a special edition of Solid State Communications on "Quantum Phases at the Nanoscale

Induction of broad immunity by thermostabilised vaccines incorporated in dissolvable microneedles using novel fabrication methods

Dissolvable microneedle (DMN) patches for immunization have multiple benefits, including vaccine stability and ease-of-use. However, conventional DMN fabrication methods have several drawbacks. Here we describe a novel, microfluidic, drop dispensing-based dissolvable microneedle production method that overcomes these issues. Uniquely, heterogeneous arrays, consisting of microneedles of diverse composition, can be easily produced on the same patch. Robustness of the process was demonstrated by incorporating and stabilizing adenovirus and MVA vaccines. Clinically-available trivalent inactivated influenza vaccine (TIV) in DMN patches is fully stable for greater than 6months at 40°C. Immunization using low dose TIV-loaded DMN patches induced significantly higher antibody responses compared to intramuscular-based immunization in mice. TIV-loaded patches also induced a broader, heterosubtypic neutralizing antibody response. By addressing issues that will be faced in large-scale fill-finish DMN fabrication processes and demonstrating superior thermostable characteristics and immunogenicity, this study progresses the translation of this microneedle platform to eventual clinical deployment

Bacterial Approaches to the Recovery of Scarce Metals

Many of the scarcest metals are critical to future energy technologies. However, these metals often have limited supplies, and their current production and recycling methods are complicated and use toxic chemicals. In order to ensure the availability of these metals alternative methods for their recovery need to be explored. This thesis describes biological methods for the recovery of some of these metals, specifically the lanthanides and tellurium. It is one of the first investigations for the biogenic recovery of either of these metals, making it unique in the field. The lanthanides are critical elements in the high performance magnets used in wind turbines, electric vehicles, and other 'green' technologies, but they are difficult to separate from one another because of their chemical similarity. We demonstrate a biogenic method based on lanthanide adsorption to the bacteria Roseobacter sp. AzwK-3b, followed by subsequent desorption as a function of pKa using a semi-continuous flow process. The desorption behavior suggests that the basicity of the individual lanthanides is important in determining their biosorption and desorption behavior. Similar selectivity was also found using phosphatidic acid liposomes. It is possible to concentrate a solution of equal concentrations of each lanthanide to nearly 50% of the two heaviest lanthanides in only two stages of enrichment, surpassing existing industrial practice. This suggests that there is an opportunity to harness the diversity of bacterial surface chemistry and liposome chemistries to fine tune the separation and recovery of these technologically important metals, and to do so in an environmentally benign manner. Tellurium is used in photovoltaic (PV) modules and thermoelectric generators, however it is not abundant in the earth's crust and is difficult to produce. We show that the hydrothermal vent microbe Pseudoalteromonas sp. strain EPR3 can convert tellurium from a wide variety of compounds, industrial sources, and devices into metallic tellurium and a gaseous tellurium species. These include metallic tellurium, tellurite, copper autoclave slime, tellurium dioxide, tellurium-based PV material (cadmium telluride), and tellurium-based thermoelectric material (bismuth telluride). Despite the fact that many of these tellurium compounds are considered insoluble in aqueous solution, they can nonetheless be transformed by EPR3, suggesting the existence of a steady state soluble tellurium concentration during tellurium transformation. Insights from these experiments on the mechanisms of tellurium precipitation and volatilization by bacteria, and their implications on tellurium production and recycling are discussed.Engineering and Applied Sciences - Applied Physic

Rare-Earth separation using bacteria

The rare-earth elements are critical to many green energy technologies but are difficult to separate from one another because of their chemical similarity. We demonstrate an alternative, biogenic method based on the adsorption of lanthanide to the bacterium Roseobacter sp. AzwK-3b, immobilized on an assay filter, followed by subsequent desorption as a function of pH. The elution desorption data suggest that the basicity of the individual lanthanides is important in determining their desorption behavior. It is found that via preprotonation of the bacteria it is possible to concentrate a solution of equal concentrations of each lanthanide to nearly 50% of the three heaviest lanthanides (Tm, Lu, and Yb) in just two passes. This surpasses existing industrial practice. The findings suggest that there is an opportunity to harness the diversity of bacterial surface chemistry to separate and recover technologically important rare-earth metals in an environmentally benign manner.Engineering and Applied Science