Current World Environment Vol. 9(3), 940-946 (2014) Bioethanol Production from Enzymatically Hydrolysed Cotton Stalk: One Approach Towards Sustainable Energy Development MIRZA ZAHEER BAIG and SMITA M. DHARMADHIKARI Department of Microbiology, Government Institute of Science, Aurangabad (M.S.)-431004, India. http://dx.doi.org/10.12944/CWE.9.3.46 (Received: July 14, 2014; Accepted: August 14, 2014) ABSTRACT: The lignocellulosic nature of cotton stalk favours to use as renewable material for variety of commercial applications. Present study was evaluating the potential of cotton stalk for bioethanol production. In this regards cotton stalk were subjected to series of treatment including pretreatment, hydrolysis and fermentation. The resultant data shows that physically pre-treated cotton stalk when subjected to 2% alkaline solution at 121 o C for 60 minute followed by enzyme hydrolysis with 100 CMC units of enzyme releases sugar of 0.49 g/g and 24.5 g/L of biomass.Furthermore when it goes to fermentation using co culture of Saccharomyces cerevisiae and Pachysolen tannophilus,givesan ethanol concentration of 9.56 g/L which corresponds to a yield of 0.191 g/g of biomass, 0.298 g/g of holocelluloses and 0.392 g/g of fermentable sugars while fermentation and sugar consumption efficiencies were recorded as 76.85% and 97.81% respectively. Key words: Cotton stalk, Bioethanol, Pretreatment, Hydrolysis, Fermentation. INTRODUCTION Worldwide increasing energy demand and decreasing fossil reservoir led to the resurgence in development of alternative fuel, which must be renewable and environmental friendly. Unlike fossil fuel, ethanol is renewable energy source produced through fermentation of sugar. Ethanol can be produced from variety of biomass and among various biomasses; lignocellulosic biomass source is plentiful and economical resource that can serve as source of ethanol production at large scale 1 . Lignocellulosic biomass sources include: agricultural wastes, industrial wastes, forestry wastes and municipal solid wastes, etc 2 . Cotton stalk which are left behind after the cotton harvest, is one of the example of a lignocellulosic agricultural waste. There are about 32 million hectares of cotton cultivable area across the world and about 10 million hectares in the country 3 . Since cotton stalk is a by-product of cotton crop; India has an abundance of this lignocellulosic biomass source. The objective of present study is to evaluate the potential of ethanol production from alkali pre- treated and enzymatically hydrolysed cotton stalk by suing co culture of Saccharomy cescerevisiae and Pachysolen tannophilus. MATERIALS AND METHODS Collection of raw material The cotton (Gossypiumhir sutum NHH44) stalkused in this research work was harvested material from the farmer’s field of Marathwada region. Physical pretreatment The cotton stalk which consist of different unwanted residues were removed mechanically by shredding followed by sundried, debarked, bailed and ground to 1mm particle size with laboratory blender and stored in tightly sealed plastic bags.