Study of the production of biodiesel by enzymatic and chemical processes from used cooking oil

TLDR: In this paper, chemical and enzymatic processes from used cooking oil (UCO) were analyzed by evaluating the quality and yield of the product obtained in each method. And the highest yield obtained was from the chemical transesterification under the conditions of 60 °C, 1% KOH and 70 min with a conversion percentage of 96.15% and an acid number of 1.33 mmKOH/g.

Abstract: The biodiesel production was analyzed by chemical and enzymatic processes, from used cooking oil (UCO), evaluating the quality and yield of the product obtained in each method. For the chemical process, an acid esterification followed by a basic transesterification was developed, (reaction temperature: 60 °C, oil:methanol 1:6 molar ratio, concentration of KOH catalyst: 1% w/w reaction times: 55 and 70 min); and enzymatic transesterification (temperature: 38 °C, oil:methanol 1:3 molar ratio, enzyme concentration lipase XX 25 split liquid: 5%, reaction times: 3 and 6 hours). Physicochemical properties (i.e. density, kinematic viscosity, moisture content, fatty acid profile, percentage of acidity, peroxides index and saponification) of the raw material were determined. Results showed the presence of oleic acid (42.45%) and palmitic acid (33.52%). The highest yield obtained was from the chemical transesterification under the conditions of 60 °C, 1% KOH and 70 min with a conversion percentage of 96.15% and an acid number of 1.33 mmKOH/g, compared to the enzymatic transesterification which registered a high acid number of 6.91 mmKOH/g and conversion percentage of 48.81% under the conditions of 38 °C, 5% of enzyme lipase and 3 hours.