Leather processing industry waste (lime fleshing): A prospective substrate for production of biodiesel

Production of biodiesel using leather industry solid wastes (leather lime fleshing) containing high fats and proteins was developed, which benefitted both the ways to manage waste along with generation of renewable energy. Oil from this waste was obtained using solvent extraction process. Acid catalyzed esterification followed by transesterification using KOH was used in this biodiesel production process. Extracted oil containing high free fatty acid of 11.19 % was subjected to acid catalyzed esterification using 80% methanol, 2.5 % H2SO4 at 70 °C for 60 min. The esterified oil than trans esterified into biodiesel using 60% methanol and 0.8% KOH at 60 °C for 120 min. Biodiesel yield was 95.81%. Characteristics of produced biodiesel like flash point (145 oC), acid value (2.7 mg KOH/g), density (0.870 g/cc), pour point (-12 oC) and viscosity (5.79 and 1.2 cSt at 40 and 100 oC respectively) etc. were determined. These characteristics were very close to the commercial biodiesel standards. The renewable leather industry waste could be a potential sources of biodiesel production and would protect environment and contribute to energy demand. Bangladesh J. Sci. Ind. Res. 57(3), 131-138, 2022