Cyanobacteria have been engineered to produce isobutanol directly. what advantage does this have over other alternative biofuels?
a. it is an inherently renewable fuel source.
b. multiple processing steps can be avoided.
c. they produce chemical energy through photosynthesis.
d. they make a biofuel alternative to gasoline.

The answer is (b.) Multiple processing steps can be avoided

Cyanobacteria are genetically engineered to produce isobutanol. It has many advantages compare to other biofuels. Cyanobacteria's necessary supplements are Carbon Dioxide, Water and Sunlight only. By this, some process can be avoided such as to source out the plant matter from food sources.

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