Cow-dung –possibility for a sustainable future biorefinery in india part-i an overview

In India, 69 %-70% population is living in rural areas where cow (Bos indicus) is principal cattle. Total Milk producing Cows in India are about 80 million and non-milk producing cows are on the order of 30 million each generates 9–15 kg dung/day. On an average in India from the non-milk producing cows 8x107 kg per day cow dung is produced. One of the serious social problems is the waste generated from stray cows and gaushalas which is not only source of solid pollutants but also run off liquid along with gaseous emission, some of which are either hazardous, lethal or mutagenic or even poisonous, or pathogenic in nature. The solutions for this major problem due to either pollution or disposal of solid wastes can be overcome by the synthesis of some of the worth-mentioning products which include bio-plastics, or bio-textiles,α-cellulose, pulp, paper and card boards for sustainable packaging,, bio-gas, bio-oils and fermentation products like ethanol, bio-composting and bio-fertilizers (N-P-K), nano-cellulose and MFC, microbial products (bacteria and enzymes), activated carbon, and fillers, bricks, silica, ceramics, and silicon-based semiconductors. In this present paper a review is made on these invaluable products with special emphasis on bio polymers and polymers from the ligno-cellulosic part of the cow dung, which in turn consists of cellulose, hemicellulose, lignin, and sometimes starch also. It is important to mention that based on recent survey the total amount of lignocellulosic part (sum of cellulose, hemicellulose and lignin) in cow dung in India is reported on the order of 52%.