Stochastic techno-economic analysis for the co-production of alternative sweeteners in sugarcane biorefineries

Abstract

The global sugar industry is stagnating due to oversupply of international markets, which requires investments in product diversification. Health concerns have also been raising questions about sugar as a sweetener. This study investigated the viability of producing alternative, low-calorie sweeteners in a sugarcane-mill-annexed biorefinery, utilising A-molasses as feedstock. Single-product and multiproduct biorefineries were simulated in Aspen Plus® to produce isomaltulose, allulose, short-chain fructooligosaccharides (scFOS) and/or thaumatin. The minimum selling prices of isomaltulose (870 $/ton), allulose (2030 $/ton) and scFOS (1540 $/ton) in the single-product biorefineries were lower than current market prices, while that of thaumatin (11 665 000 $/ton) was higher. However, single-product biorefineries would oversupply the market. In multiproduct scenarios the available A-molasses was shared between isomaltulose, allulose and scFOS in one biorefinery, to produce ≤15% of the global market for each, using either six bioreactors operated continuously, or one bioreactor shared between six process steps through scheduling. The shared-one-bioreactor had a higher deterministic IRR (60%) than the six-bioreactor scenario (50%). Stochastic financial analysis confirmed the higher IRR for the shared-one-bioreactor (41.39%) compared to the six-bioreactor (36.07%) scenario, reflecting price variabilities’ impact on biorefinery profitability. Multiproduct scenarios were deemed economically attractive for A-molasses diversion from a typical sugarcane mill.