Process design and economic evaluation of green extraction methods for recovery of astaxanthin from shrimp waste

Abstract

Sunflower oil (SF) and its methyl ester as well as supercritical fluid (SC-CO2+ 5wt% EtOH) have recently been shown as potential green solvents which could substitute traditional organic solvents. This study investigates the economic feasibility of using these green solvents to extract astaxanthin (ASX) from shrimp processing waste. The feasibility of commercial use of the green solvents under plausible process conditions is compared to extraction with a mixture of hexane: isopropanol (Hex:IPA). The process flowsheets describing these processes were modelled by means of SuperPro Designer and Aspen Plus. The highest ASX extraction yield was achieved using Hex:IPA (26.4kg/year), the lowest yield using SC-CO2+ 5wt% EtOH (12.8kg/year). The cost of producing pure ASX for these processes was about 0.6 and 0.82$/mg of ASX, respectively. The concentration of ASX obtained by the extraction processes with SF or the methyl ester of SF (ME-SF) was 2.5 and 153ppm with a production cost of 0.06 and 0.16$/mg of ASX, respectively. In addition, shrimp feed production was considered as a feasible application of the low concentration ASX obtained by SF extraction. A combination of ASX extracted with SF and synthetic ASX yielded a shrimp feed production cost comparable to the current market price. The calculated feed price based on the ASX production cost of the other green processes, ME-SF and SCFE, resulted in a significantly higher production cost.