ABSTRACT
The increasing economic growth and the prosperity has been accelerated worldwide with the increasing demand on the energy mostly generated from fossil fuels since the beginning of the industrial revolution in the mid eighteenth century. This has brought about rapid global warming caused by the emission of the greenhouse gases such as CO2, resulting in the disastrous climate change, and this problem will become endangering even to the level of human survival by the end of this century. It is, therefore, the time to take action to prevent further global warming by employing the alternative clean renewable sources of energy. Among the renewable energy sources such as nuclear, solar, wind energies, etc., bioenergy seems to be the most promising alternative source of renewable energy in the long range future.
The so-called 1st generation biofuels have been produced from corn starch and sugarcane in USA and Brazil. However, this causes a problem of the so-called “food and energy issues” as the production scale increases. The 2nd generation biofuels production from lignocellulosic biomass has thus been paid more attention recently. However, it requires energy intensive pre-treatment for the degradation of lignocellulosic biomass. The 3rd generation biofuels production from photosynthetic organism such as cyanobacteria and algae has also come under attention, but the cell growth rate and thus the productivity of the fuels is significantly low. The typical processes for biofuel and biochemical production from biomass include pre-treatment of biomass, saccharification, fermentation, and separation of the dilute fermentation broth followed by purification.
