Cleaning Up Wastes
Excerpted from BIO. "Protecting Our Environment" Washington, D.C.: Biotechnology Industry Organization, 1992.
The use of biotechnology to solve environmental problems, according to William K. Reilly, former head of the Environmental Protection Agency, "could be - should be - an environmental breakthrough of staggering positive dimensions."
Everything under the sun degrades, or breaks down, into different materials. Fallen leaves become compost, iron rusts, milk turns sour, and food 'goes bad.' Just as light, heat, and moisture can degrade many materials, biotechnology relies on naturally occurring, living bacteria to perform a similar function. Some bacteria naturally 'feed' on chemicals and other wastes, including some hazardous materials. They consume those materials, digest them, and excrete harmless substances in their place.
For decades now, municipalities have used biological methods to treat their sewage, and industry has used secondary aerobic treatment to remove harmful materials from liquid wastes. Biological treatment is not a new idea. What is new is the expanded range of biotreatment capabilities offered by the science of biotechnology.
Bioremediation uses natural as well as recombinant microorganisms to break down toxic and hazardous substances already present in the environment. Biotreatment is a broader term, which refers to all biological treatment processes, including bioremediation. Biotreatment can be used to detoxify process waste streams at the source - before they contaminate the environment - rather than at the point of disposal. This approach involves carefully selecting organisms, known as biocatalysts, which are enzymes that degrade specific compounds, and define the conditions that accelerate the degradation process.
Living Off a Landfill
Vast numbers of bacteria exist naturally in the prevailing conditions in landfills and other solid waste sites. Some of those bacteria consume, or degrade, different types of waste present at the site. But they do it slowly.
Scientists today can examine a landfill and determine not only what bacteria are degrading which materials in it - including any hazardous materials - but which do it fastest, most completely, and under what optimum conditions.
Armed with this knowledge, they can clone the most efficient strains of naturally occurring bacteria, reproduce them in quantity, and apply them to the site. In effect, they can create a customized army of waste eaters.
Oil for Dinner
Some bacteria literally 'live on oil,' just as some people live on meat and potatoes. And they consume it with just as much relish.
Following the major oil spill in Alaska's Prince William Sound, the Environmental Protection Agency brought in natural oil-eating bacteria to help clean up the mess. Follow-up studies suggest that the microbes did as good a job in cleaning up soiled beaches as high-pressure hoses and detergents could have done. "It was almost as if we had brought in fresh rock," stated the EPA's project manager after visiting the site.
Such bioremediation cannot only help to clean up oil spills, but also chlorinated chemicals and leaks from storage tanks.
Using naturally occurring bacteria for environmental purposes is a relatively simple procedure of identification, cloning, and mass production.
Biotechnologists using recombinant DNA technology - the principal tool of genetic engineering - can recombine, or mix-and-match, the most desirable traits of several bacterial species. They can, for instance, extract the gene from one strain that allows it to 'feed' on PCBs or other hazardous wastes, then take the genes that allow another bacterial strain to withstand wide temperature ranges - lack of oxygen or other environmental extremes - and transplant them into a common, harmless bacterium that can be mass produced easily. The result is an organism custom-made to 'eat up' a specific problem waste at a specific site under specific conditions.
This technology holds the potential to solve many environmental problems from the past, and leave our children an environment cleaner than we inherited from our parents.
Of equal, or perhaps even greater importance, biotechnology can eliminate hazardous pollutants at their source before they enter the environment. Every year, some 5 billion pounds of 320 potentially harmful chemicals are released into the environment. The EPA has targeted 17 of those chemicals for massive reductions. Biotreatment with naturally occurring biocatalysts has been demonstrated to almost completely eliminate one of these chemicals, methylene chloride, a suspected carcinogen, from industrial process streams. About 130 million pounds of this compound are currently discharged each year in manufacturing process wastes.
Special bacteria in a bioreactor can virtually eliminate methylene chloride from industrial waste water. They reduce concentrations from over 1,000,000 parts per billion to less than 5 parts per billion - far below the EPA's permissible guidelines. The bacteria in the bioreactor consume the chemical and convert it to water, carbon dioxide, and salt. They permanently destroy the hazardous material and eliminate any need to recover it, transfer it, or dispose of it.