Energy flows from many sources, exists in a variety of interchangeable forms, and drives all systems. New and renewable sources of energy can make significant contribution, but their role and potential in the short term should not be overstated. It has been estimated that new and renewable sources of energy at present meet only 5-10 per cent of global energy-requirements, which may hopefully go up to 30% by 2050 A.D. Renewable energy resources and technologies have the potential to provide long-lasting solutions to the problems faced by the economic and environmental sectors of a nation. In the present work, cotton waste from textile mills were collected, pooled, processed and used as source for the production of bio-ethanol by microbial saccharification and fermentation process. The cotton waste was subjected to acid and alkali pretreatment to expose the sugars for further enzymatic hydrolysis by the cellulase enzyme produced from Trichoderma reesei. The results of pretreatment showed that the acid pre-treated substrate enhanced enzyme action and released more amount of sugar compared to the alkali pre-treated substrates. The amount of sugar released was found to increase with the increasing concentration of acid (110 mg/ml) or alkali (70 mg/ml). The sugars were then fermented with Saccharomyces cerevisiae to obtain alcohol and the amount of alcohol produced in batch and fed batch fermentation were 90 and 86 ml/l respectively. Thus, the results of the present work clearly revealed that the cellulosic cotton wastes could be converted into bioethanol with enzymatic hydrolysis followed by fermentation.
