Beer and Bacteria to be used in Toxin Cleanup

GospelHead821 writes "According to this article in Popular Science, a chemistry student at the University of Tulsa is driving research into use of toxin-munching "sulfate-reducing bacteria" (SRBs) to help cleanup toxic, solid effluent from abandoned zinc and lead mines near her home. Where does the beer come in? Apparently, it has proved an excellent food source for the bacteria and helps to extend the lifespan of the normally short-lived SRBs by several months. Currently, the procedure is in the testing phase, with models being employed to simulate the conditions that would be present in a large-scale detoxification plant, which in turn, is based on the natural wetlands from which these bacteria hail."

Comments

Where do the heavy metals go?

[caesar-auf-nihil]

While this bioremediation technology looks real cool at first glance, and creates lots of beer jokes, I can see one potential flaw with it, unless I'm missing something. The flaw is that all that toxic lead and zinc have to go somewhere, even if the bacteria chew it up and remediate the soil. So where are the heavy metals going?

My guess is that they are taken up by the bacteria and somehow locked into a protein structure, putting the metal in the bacteria cell and not in the ground. Okay fine, you've gotten the toxic metal out of the ground and into the bacteria, but now what? If the bacteria are just left in the soil, they'll eventually decay and rather than having large chunks of zinc and lead laying around, you'll have atomisically dispersed metal all over the place.

I wish the popular science article had been more specific or verbose in how the whole thing would be engineered. My guess is that they'll have to somehow separate the soil from the bacterial colonies and burn the colony to collect the pure metal. The metal can then be recycled or stored safely. Separating the soil from the bacteria though is going to be very difficult.

I remember a similar technology that used plants to remove mercury from contaminated water streams rather than using bacteria. The scientists took a swamp plant that naturally had an affinity for mercury ions, and selectively bred/genetically engineered the plants to have even more affinity for the toxic mercury ions. The plants roots when then dangle in the waste streams, removing the ions and moving it to the leaves (natural defense mechanism as it turns out - animals and some bugs don't want to eat mercury-toxic leaves). After awhile the plants could be "harvested" and burned, where the mercury metal could then be collected, distilled, and recycled.

Given the sucess of the above approach (its now used by several companies that sometimes have mercury metal in their chemical waste streams) I'm surprised that a similar approach isn't used here.

If any of you out there know how this whole process works, or where these metals are going, please let me know via this forum, I'm very interested in finding out.

Re:I'm sceptical

[Anonymous Coward]

I may be mistaken, but isn't sodium bisulfite mainly used in wines? I thought it needed to be in an acidic environment before it had any anti-bacterial properties. Beer wouldn't be acidic enough. Thats what I was told, anyways...