Comparison of kinetic biodegradation of potato starch based and corn starch based low density polyethylene compound in aerated sludge Mehdi Borghei 1 , Shahrzad Khoramnejadian* 2 , Bijan Hejazi 1 1 Sharif University of Technology, Tehran, (IRAN) 2 Department of Environment, Damavand Branch, Islamic Azad University, Damavand, (IRAN) E-mail : khoramnezhadian@yahoo.com ABSTRACT The biodegradability rates of two different kinds of polyethylene bonded with corn and potato starch are studied in this paper. While it is usual to use soil as the environment for biodegradation, an aerated sludge tank was used in this study which offers a richer microbial medium and increases the rate of biodegradation. The biodegradability is determined by two ways: first, comparing differences in the weight change of two samples, one placed inside distilled water and the other placed in aerated sludge tank. Second test for biodegradation is by examination of FTIR spectroscopy. Through FTIR spectroscopy, the biodegradability rate and reduction in some of the existing bonds in polymer before and after placing the samples inside aerated sludge tank is exhibited and the consumption of polymer by microorganisms is also revealed. Kinetic correlations for both samples are presented which shows that the kinetic rate closely follows limiting first order reactions.  2013 Trade Science Inc. - INDIA KEYWORDS Starch; Biodegradation; Kinetic; Low density polyethylene; FTIR. INTRODUCTION In recent years, biodegradable polymers have at- tracted special attention of researchers with respect to reducing the volume of solid wastes [1,2] . Biodegradable polymers are materials that could be converted to natural compounds such as water, CO2, methane and other biological components by means of microorganisms such as fungi, bacteria, algae and other natural agents [3,4,5] .Most of the biodegradable polymers were developed by blending petroleum based polymers such as Low Density Polyethylene (LDPE) with natural bio- degradable materials. This method not only conserves the environment, petroleum reservoirs and landscapes, but also decreases CO2 production and presents a green solution in a sustainable development [5] . Study on starch-based synthetic polymers began in 1970s when environmental issues attracted attention [6] .Starch is an abundant, biodegradable, ca- pable of recycling and inexpensive natural polymer which is obtainable from many botanical sources [7] . Starch is composed of two parts: amylose and amylopectin whose percentages are different in various kinds. On the contrary to amylose, amylopectin is branched and forms the water soluble part of the starch [8] . The pro- BTAIJ, 7(5), 2013 [163-168] BioTechnology An Indian Journal Volume 7 Issue 5 BioTechnology ISSN : 0974 - 7435 FULL PAPER