Every Day Roles

Some people think it would be great if scientists could wipe out all the microbial bugs! Should we do it, and why or why not?

We get a lot of requests to track down the nasty bugs that are making people sick. It's true that some microbes cause health problems such as strep throat, chickenpox and the common cold. Unfortunately, because a small number of microbes cause disease, all microbes have got a bad rap.

It seems only a few bad microbes get almost all the press. You just don't hear as much about all the many GOOD things microbes do every day.

So we've created our own bug gallery of some microbe heroes who make our lives better.


		Microbe Involved Aspergillus niger [fungus] and other species What it Does After being grown in huge nutrient-filled tanks called fermenters, the beefed-up fungi make large quantities of enzymes, some of which are used to turn animal hides into leather goods. Microbe Involved Aspergillus oryzae [fungi]; Peediococcus halophilus [bacterium]; Zygosaccharomyces rouxii [fungus]; Torulopsis species [fungus] What it Does Aspergillus gets things started by breaing down proteins in soybeans. Zygosaccharomyces and Torulopsis break down additional proteins in beans and wheat, giving soy sauce its distinctive flavor and rich smell. Microbe Involved Lactobacillus acidophilus (lack-toe-bah-sill-us acid-off-ill-us) What it Does Acidophilus bacteria breaks down sugars and carbohydrates in milk, turning it into yogurt. This process is called fermentation. Microbe Involved Saccharomyces cerevisiae (sack-arrow-my-seas sair-uh-vis-ee-ay) What it Does Saccharomyces is also known as Baker's Yeast because it is used to make bread rise. This fungus also breaks down the natural sugars in grains or other starchy ingredients into carbon dioxide and ethanol (a.k.a. alcohol). Microbe Involved Streptomyces (strep-toe-my-seas) What it Does Streptomyces is a soil bacteria that makes streptomycin, an antibiotic used to treat infections. Fungi and bacteria produce powerful antibiotics such as penicillin (pen-ih-sill-en) and tetracycline (teh-truh-sigh-klin). These are drugs we use to fight off nasty bacteria that cause sore throats, ear infections, diarrhea and other discomforts. Microbe Involved Pseudomonas putida (sue-doe-moan-us poo-tea-dah) What it Does Pseudomonas cleans waste from sewage water at water treatment plants. Microbe Involved Escherichia coli (Esh-er-ish-e-ah coal-eye) What it Does E. coli is one of many kinds of friendly microbes that live in your gut and help you digest your food every day. Microbe Involved Arbuscular mycorrhizas (ar-bus-que-ler my-kuh-rye-zuh) What it Does Arbuscular is part of a soil-living fungus family. This fungus helps crops take up nutrients from the soil. Microbe Involved Bacillus thuringiensis (bah-sill-us ther-in-gee-in-sis) What it Does Bacillus thuringiensis is also know as "Bt." This common soil bacterium acts as a natural pest-killer in gardens and on crops. Microbe Involved Methanotroph (meth-an-oh-trof) What it Does Methanotrophs eat methane gas to clean up hazardous waste dumps and landfills. These methane-munching bacteria make an enzyme that can break down more than 250 nasty pollutants into harmless molecules. By piping methane into the soil, we can increase growth of the methanotrophs that normally live in the polluted soil. More methanotrophs means faster pollution break up. Microbe Involved Marine Bacteria What it Does We're using bacteria as one of the tools to clean up oil spills. These bacteria chow on the oil, turning it into carbon dioxide and other harmless by-products. Microbe Compound Involved Enzyme What it Does Microbes make compounds called enzymes that we use in making hundreds of products. We grow billions of bacteria in giant fermenting tanks, then break them apart to get their enzymes for making soy sauce, soda, beer, wine, cheese, infant formula, chewing gum, leather goods, paper, laundry detergent, and even the stone-washed look on blue jeans. Microbe Involved Lactobacillus delbrueckii What it Does Lactobacillus turns lactose, the sugar in milk, into lactic acid that wards off microbes that cause spoilage. Microbe Involved Aspergillus oryzae [fungus]; Kluyveromyces lactis [fungus] What it Does These fungi produce lactase, an enzyme that breaks down lactose, enabling people with lactose intolerance to drink milk. Microbe Involved Propionibacterium freudenreichii What it Does This bacterium produces carbon dioxide gas bubbles that burst in ripening cheese, leaving this cheese's trademark holes. Microbe Involved Acetobacter What it Does Acetobacter modifies glucose, making vitamin C as a by-product. Microbe Involved Lactobacillus sanfrancisco What it Does This bacterium gives sourdough its unique flavor by producing lots of tangy lactic acid. Microbe Involved Xanthomonas campestris What it Does This bacterium produces a slimy outer couting called xanthan. Xanthan gum is used as a thickening and stabilizing agent in many common products including water-based paints and cosmetics. Microbe Involved Saccharomyces carlsbergensis What it Does This fungus breaks down the natural sugars in grains to form ethanol and carbon dioxide (a.k.a. beer). Microbe Involved Thermus aquaticus What it Does This bacterium makes a special enzyme, polymerase, that enables scientists to make many millions of copies of DNA using a process called PCR (polymerase chain reaction). The PCR procedure produces a lot of heat; because Thermus aquaticus lives in hot springs, its polymerase can withstand high temperatures and still work.