A factory plans to make four products with microbes…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A factory plans to make four products with microbes. Name one microbe for each, and say whether it is a bacterium, a fungus or a yeast.
- Vinegar, whose acid is acetic acid.
- Citric acid for soft drinks.
- Butyric acid for flavours.
- Lactic acid for foods.
- Whisky: name the microbe that makes the ethanol, and the step that follows.
Need a reminder? The key ideaShow
Yeast ferments sugar to ethanol. The best possible yield is g of ethanol from g of glucose, and the density of ethanol is g per mL. Wine and beer are not distilled. Whisky, brandy and rum are. Citric acid: Aspergillus niger. Acetic acid: Acetobacter aceti. Butyric acid: Clostridium butylicum. Lactic acid: Lactobacillus.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) Acetobacter aceti, a bacterium.
Step 2. (b) Aspergillus niger, a fungus.
Step 3. (c) Clostridium butylicum, a bacterium.
Step 4. (d) Lactobacillus, a bacterium.
Step 5. (e) The yeast Saccharomyces cerevisiae ferments the malted cereals into ethanol. The fermented broth is then distilled.
Answer: (a) Acetobacter aceti; (b) Aspergillus niger; (c) Clostridium butylicum; (d) Lactobacillus; (e) Saccharomyces cerevisiae, then distillation.
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