This study was conducted during March to May of 2010 dry season, giving prime thrust to determine the metal concentrations in commercial fish species of Catla catla and Labeo rohita, collected from various points along the river Cauvery. The liver, gill and muscle tissues of fish were analyzed for Fe, Pb, Zn, Ni, Mn, Cu, Cr and Cd using Atomic Absorption Spectrophotometry (AAS-model: 6300). The Catla catla has shown more accumulation potency for all the metals than Labeo rohita. The liver in both fish species has better accretion capacity compared to gill and muscle and the same was noticed by bioaccumulation factor. The results of bioaccumulation factor were in the order of Ni > Zn > Cu > Mn > Fe > Cr > Pb > Cd. Elevated trend was noticed among the essential metals and decreased trend among the nonessential metals were observed in both fish species.

Unrefined rice bran oil (UNRFRBO) with high free fatty acids (FFA) is used as a source for the production of unrefined rice bran oil methyl ester (UNRFRBOME). Three-stage transesterification process is successfully used. Initially, the FFA of UNRFRBO is reduced to 1% (0.8%) by using two stages esterification process with methanol in the presence of acid (H₂SO₄) as a catalyst. Finally, biodiesel has produced by alkaline (NaOH) catalyzed transesterification process which has designed according to the central composite design. 90% has obtained at the optimum values of CH₃OH (20% v/v of oil), NaOH (1.0% w/v of oil), reaction time (60 minutes) and reaction temperature (55^°C to 60^°C).