Enzyme based cleaner process for enhanced recovery of lipids from tannery fleshing waste

摘要

The lipid content of tannery fleshing waste is remarkable and it is essential to develop an efficient process for extraction of lipids as a source for biofuel application. A protease assisted method was developed for the extraction of lipids from tannery fleshing waste using Bacillus subtilis MTCC 6537 protease. The lipid yield was 14.96%, when extraction was carried out with 100 g of fleshings and 300 U of protease at 40 degrees C for 60 min. This yield was 23.12, 36.5 and 43.18% higher than the lipids extracted by thermal hydrolysis, Soxhlet extraction and Bligh & Dyer method, respectively. There was no significant difference in the yield of lipids with 1 kg of fleshings under above conditions. Moreover, the solvent consumption was reduced in the enzymatic method by 1.9-7 times towards production of 1 kg of lipids and reusage of solvents for subsequent batches of extraction makes the process green. The enzymatic method is also industrially viable due to increased lipid yield and mild reaction conditions, although the energy requirement was comparatively higher than Bligh & Dyer method. Physicochemical characteristics of lipids reveal that it could be a feasible and potential feedstock for biodiesel production. The extracted lipids were analyzed using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The results on gas chromatographic analysis showed that fleshings lipids contained palmitic acid (26.46%), stearic acid (17.25%), oleic and linoleic acid (47.10%), which are mainly involved in the production of alkyl esters. (C) 2017 Elsevier Ltd. All rights reserved.