The production of various commodity chemicals including fine chemicals, pharmaceuticals, bulk chemicals, plastics, and fuels is based on fossil resources such as petroleum. However, the limited reserves and ever-increasing demand of petroleum lead to the rapid elevation of its price. In addition, the traditional chemical processes using petroleum as a raw material have been imposing a serious environmental burden to our planet including global warming. These problems can be alleviated substantially by employing biological raw materials and bioconversion processes. Industrial biotechnology is expected to significantly complement or replace the current petroleum-based industry and to play an important role in bringing about so-called ‘bio-based society’.