Biodiesel produced from crude, degummed, neutralized and bleached oils of Nile tilapia waste: Production efficiency, physical-chemical quality and economic viability

Abstract

Crude oil extracted from tilapia heads and oils obtained from different steps of its refinement process (physically degummed, chemically degummed, neutralized, and bleached oils) were used as raw materials for biodiesel production. Extraction and refinement of the oil and, after, production and economic viability of the different biodiesels were performed. The heads corresponded to 45% of waste from Nile tilapia and of extractions yield was around 80–85% of the crude oil. The highest biodiesel yields were with the neutralized oil (80.35%, w w−1) and chemically bleached oil (83.55%, w w−1). The lowest biodiesel production costs were by the physical degumming, chemical degumming, and neutralization steps, which presented an average cost of 0.181 US$ kg−1. Neutralized oil in the transesterification reaction, besides presenting the lowest biodiesel production cost, provided a suitable product with the acid value, kinematic viscosity, and flash point according to ASTM standard for biodiesel. Regardless of the refinement process, the degradation ranges of the oil samples were 350–550 °C. TLC, GC, and FTIR confirmed the triglycerides conversion from tilapia oil into biodiesel. Based on results, Nile tilapia neutralized oil showed suitable characteristics, becoming a promising source for biodiesel production of the quality and economically viable.