Comparison of immobilized and free enzyme systems in industrial production of short‐chain fructooligosaccharides from sucrose using a techno‐economic approach

Abstract

AbstractShort‐chain fructooligosaccharides (scFOS) are nutraceuticals with numerous applications in the food and pharmaceutical industries. The production of scFOS using immobilized biocatalysts offers some functional and technical advantages over free enzyme counterparts. To investigate the economic potential of the immobilized enzyme system relative to the free enzyme system, a techno‐economic comparison was conducted on three methods of scFOS production (powder and syrup forms) at a capacity of 2000 t per annum (tpa) by enzymatic synthesis from sucrose: the free enzyme (FE), calcium alginate immobilized enzyme (CAIE), and amberlite IRA 900 immobilized enzyme (AIE) systems. These processes were simulated in Aspen Plus to obtain the mass and energy balances and to estimate the operating and capital costs, followed by economic evaluation and sensitivity analysis. Profitability analysis showed that all three systems are economically viable as their associated minimum selling prices (MSP) were well below the scFOS market price of 5 $ kg−1. However, the FE system was the most profitable with the lowest MSP of 2.61 $ kg−1 because the savings on cost as a result of enzyme immobilization could not offset the additional costs associated with immobilization. Sensitivity analysis demonstrated that total operating cost, fixed capital investment, and internal rate of return (% IRR) have the greatest effects on the MSP. Furthermore, the syrup form of scFOS production leads to 29% less MSP, compared to powder form. In addition, the studied plant capacities of 5000 and 1000 tpa showed 10% and 16% reductions on MSP respectively. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd