**1. Introduction**

Bio-alcohol is an environment-friendly clean fuel for transportation application and convertible to various other fuel compounds. It is also a means of reducing greenhouse gas and fossil fuel consumption. Bio-alcohol includes various formulas such as bio-ethanol and bio-butanol. R & D for commercialization of bio-butanol is currently active which can replace existing petroleum fuel or can be converted to other forms of fuel. Bio-ethanol is collectively called as bio-alcohol in view of worldwide total production volume and quantity in use. Bio-ethanol among other bio-alcohols is mainly considered in the present survey, especially related to its current trend of conversion technology to other fuel formulas. Korean domestic bioalcohol technology boasts of its long history in alcohol liquor industries. However, its food-based raw material casts a negative perspective, and technical solution for diversion to nonfood-based raw material is to be sought after. As an example, bioalcohol production from cellulosic biomass as raw material involves the introduction of breaking method for the strong chemical bonding of cellulosic biomass to improve conversion efficiency, which was made possible by pre-treatment technology. However, high production cost incurred from pre-treatment process technology and high enzyme cost for bio-treatment process are another technical barrier, and it has to be overcome by overall process and energy cost reduction.
