A research team led by Professor Kwon In-chan in the Department of Materials Science and Engineering at the Gwangju Institute of Science and Technology (GIST) said on the 22nd that it developed an eco-friendly bioconversion technology that converts the byproduct "molasses" from the sugarcane refining process into the high value-added substance "D-mannitol" using only enzyme reactions.
The research team focused on molasses generated when processing sugarcane or sugar beets. Molasses is a viscous byproduct that, in addition to sugar, contains a mixture of glucose, fructose, and minerals. It has mostly been used only as livestock feed or a low-cost ethanol feedstock, and high value-added uses have not been achieved.
The research team newly designed a three-step enzyme reaction system that converts molasses into D-mannitol using only enzyme reactions without chemical treatment. D-mannitol, a type of natural sugar alcohol, is a high value-added substance used as a sweetener, stabilizer, or therapeutic agent across various industries including food, pharmaceuticals, and cosmetics.
In the developed system, three enzymes act as catalysts found in nature and work step by step to induce a cascade reaction from sucrose to glucose, fructose, and D-mannitol. The research team also implemented a self-sufficient system that does not require supplying additional cofactors from outside.
The research team built two types of enzyme reaction systems and compared their performance. First, in a two-step process applying the optimal conditions for each enzyme step by step, the D-mannitol conversion efficiency was about 92%. In the process where all enzymes were mixed and reacted at once, the efficiency rose to 95%.
In this process, they confirmed that D-glucono-1,5-lactone, generated as glucose is oxidized, can be used as another value-added compound.
Professor Kwon In-chan said, "This study is an upcycling technology that can obtain high value-added compounds from industrial byproducts that were being discarded, securing both environmental friendliness and economic efficiency," and added, "We expect it to expand into a sustainable bioproduction process in various industries such as food, pharmaceuticals, and energy going forward."
The study was published online on Sept. 30 in the international journal "Industrial Crops and Products."
References
Industrial Crops and Products(2025), DOI: https://doi.org/10.1016/j.indcrop.2025.122016