Isolation and Characterisation of Starch Degrading Lactic Acid Bacteria

Abstract

Judicious recycling, reprocessing and finally utilization of food processing residues offer potential of returning these by-products of agro based industries, to beneficial uses rather then their discharge to the environment which might cause detrimental environment effects. Effective utilization of food residues can occur if through biotechnological interventions these wastes can be made utilizable by a minor industry. Food industry produces large volumes of wastes, both solids and liquids; this waste pose increasing disposal and pollution (High BOD or COD) problems and represents a loss of valuable biomass and nutrients. However, despite of their pollution and hazard aspects, in many cases, food processing wastes have a good potential for conversation into useful products of higher value as by-product, or even as raw material for other industries. Organic acids are examples of such valuable by-product of the fermentation of high carbohydrate containing industrial substrates. For instance, potato-processing plants release an appreciable amount of starch in wastewater streams, additionally; potatoes, which do not fit the standard quality criterion, are discarded. They therefore could be utilized cheaply as substrate for microorganisms producing intermediate volume high value organic acids like lactic acid. Lactic acid, an intermediate-volume especially chemical is under increasing demand in Food, Pharmaceutical and Chemical Industries and for production of Poly lactic acid polymers, which possess excellent biomedical applications. The global production of this organic acid is estimated to be 100 million pounds/yr and is expected to grow by 8.6% annually (Narayanan et. al, 2004.) Lactic acid is currently manufactured either through chemical or microbial route via fermentative mode. In India, the annual production capacity of lactic acid is 6000 T and an estimate gap of 2300 T in supply by the year 2015 have been predicted, if the present level of production is not increased (TIFAC 2001). Wastes containing starch generated from food processing plants may be regarded as a viable option for meeting this growing demand for lactic acid, if appropriate biotechnological interventions are used. Specific sectors amongst the Indian food processing industry need to be targeted. The snack food sector have expanded significantly in the recent years, for instance the Indian snack market is currently one of the largest snack markets in the Asia – Pacific Region (valued @ $307.7 million in 2001) ( http:www.stat-usa.gov/). Potato chips are by far the largest product category within snacks, and generate 85% of the total market revenue. Additionally, the market for branded potato chips has been growing rapidly at approximately 20% annually. Consequently there has been a tremendous increase in potato consumption by this sector with a current average of approximately 450 MT/day.