or biases, and they therefore do not represent conclusions or recommendations of the workshop organizing committee or the National Research Council.

DEFINING “BIOINPIRED”

Given the diverse disciplinary backgrounds of the workshop participants, a key question raised was “what does bioinspired mean?”

Mimicry Versus Inspiration

The term “bioinspired” is often used interchangeably with the term “biomimicry.” However, biomimicry really means to copy or recreate natural systems, whereas bioinspired is about learning from nature to make something new. One participant explained that bioinspired really means to deeply understand the biological system being studied. Only when the biology is understood at the most fundamental level will it be possible to redesign it and create a better system. Artificial systems are desired over natural systems because biological systems often contain extra “baggage” (i.e., components that are useful for the organism, but not necessarily for the desired application function). Although there are advantages to natural systems—for example, proteins can be excellent catalysts in the form of enzymes—they tend to have limitations. In the cell, enzymes need to compete with many other substrates. Cells spend a lot of time and energy trying to engineer specificity, which may or may not be needed for energy applications. In most cases, much of the natural structure is probably not needed in artificial systems. The specificity may not be needed where the enzyme can be artificially inundated with a large amount of substrate.

One example discussed by some workshop participants is nitrogenase, which is a very important nitrogen-fixing enzyme related to both agriculture and energy. James Liao noted that about 5 percent of the energy used in the world is spent in the synthetic nitrogen-fixing Haber process (catalytic reaction of hydrogen and nitrogen to produce ammonia) (Smith, 2002). Unfortunately, nitrogenase cannot currently serve as an alternative method for large-scale nitrogen fixation to compete with the Haber process. The enzyme utilizes a very complicated process, involving 16 adenosine triphosphates and many electrons. Despite all the efforts to study nitrogenases for many decades, the mechanism of the enzyme is still unknown. Liao said that if someone could understand nitrogenase better or design an artificial enzyme based on or inspired by nitrogenase, it could be a major contribution to reducing the amount of energy used in the world for nitrogen fixation.

Many participants considered biomimicry to be a nearly impossible



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