1 Introduction to the Algae

The algae are a heterogeneous group of organisms that exert profound effects in today’s world and have been doing so for billions of years. For example, as a result of photosynthetic activities, algae generate a large fraction of the oxygen present in Earth’s atmosphere and produce an enormous quantity of organic carbon. Much of this organic carbon serves other organisms as food, and the expensive oil that helps power modern life largely originates from the organic components of algae that lived hundreds of millions of years ago.

Rather than waiting hundreds of millions of years for new fossil fuels, modern biotechnologists and engineers are developing new ways to generate sustainable fuels by using algae. Biofuels produced from algae and other sources may help reduce human reliance on fossil fuels. Humans use algae in many other ways. Certain algal species are widely used as convenient laboratory systems; such small and fast-reproducing green “lab rats” have revealed essential information about the biochemistry and molecular biology of photosynthesis and other cellular processes. Algae are also harvested from nature for the extraction of industrially useful products, some of which cannot be obtained in any other way. Flavorful or nutrient-rich algae are grown as aquaculture crops for direct use as human food (e.g., sushi), or as food sources for fish and shellfish farming operations. Algae can also be used to remove pollutants from sewage and agricultural effluents before they are returned to nature.