2^nd World Bioenergy Congress and Expo

The present study describes the optimization of enzymatic hydrolysis and transesterification of leather fleshing waste for biodiesel recovery. Around 70,000 tonnes of leather fleshing (LF) waste is generated from 2300 tanneries in India. The LF is presently been managed by open dumping, composting, incineration, land filling which triggers primary, secondary and tertiary environmental impacts such as ground water contamination, unknown diseases etc., However, the amenability of this highly fat rich LF waste becomes an excellent substrate for biodiesel recovery converting waste into wealth. The LF collected from a tannery was subjected to the process of enzymatic hydrolysis, with naturally available enzyme sources from primary sludge, anaerobic sludge and chicken waste for 8 days at 40°C using soluble COD (CODs). Among different sources of enzyme substrate used with LF, the anaerobic sludge recorded maximum hydrolysed soluble COD (CODs), (1,92,000 mg.L-1) at the pH of 8.2. This was corroborated well with protease, lipase and amylase activities and their reduction in protein, fat and carbohydrate levels with elapsed time intervals. For instance, the maxima lipase and protease activity was found to be in anaerobic sludge as 71.44 units.mL-1 and 0.80 units.mL-1 whereas, the minima was recorded as 6.39 units.mL-1 and 0.01 units.mL-1 respectively. The FFA level was observed in the mesophillic reactor as 3.2% using anaerobic sludge which was found to be maximum when compared to primary sludge and their profile was studied through FTIR analysis before and after transesterification. The efficiency of transesterification with an optimised enzyme source (anaerobic sludge) was studied at different methanol:KOH ratio, reaction time and mixing conditions found to be maximum at 3:1 mixing ratio, reaction time 2 hrs and mixing conditions of 500rpm respectively. The mass balance analysis revealed that each kg of leather fleshing waste material yielded 80-100mL of biodiesel which becomes a techno-economically viable solution for the sustainable solid waste management for leather fleshing waste.