Chemo-enzymatic three-step conversion of glucose to kojic acid

Abstract

A method for producing kojic acid from glucose via glucosone using a chemo-enzymatic three-step approach was developed.

Hydrogenation of crude and purified d-glucosone generated by enzymatic oxidation of d-glucose

“…26,27 The crude D-glucosone, obtained from MetGen Oy, was only subjected to ltration through a 0.45 micron lter in order to remove enzyme particles aer the enzymatic process where D-glucose is oxidized to D-glucosone. 6 A portion of the crude D-glucosone was then further puried by column chromatography to obtain the puried D-glucosone used in the hydrogenation test reactions. The catalysts screened in the batch reactor were Ru/C, Ru/Al 2 O 3 , Ru on nitrogen doped carbon nanotubes (NCNT), Cu/SiO 2 , and RANEY® nickel.…”

“…The smaller pores are blocked entirely due to fouling, increasing the apparent average pore size measured by nitrogen physisorption. Previously, it has been shown that D-glucosone has a tendency to oligomerize or polymerize at temperatures above 50 C. 6 The difference in mass balance closures probably results from the formation of polymers, which are deposited on the walls and adsorbed on the catalyst due to low solubility in water, resulting in fouling.…”

“…[1][2][3][4][5][6] In 6 h, 80% yield of Dglucosone can be achieved and in 10 h >95% is obtained. 6 Similar to other carbohydrates, D-glucosone exhibits congurational equilibrium in aqueous solutions, where only hydrated forms of D-glucosone have been observed. 7 Several hours are required to achieve equilibrium, the composition of which varies depending on temperature, pH, and concentration.…”

“…8 While until now the use of D-glucosone has been limited due to its high price and limited availability, it has been shown recently, for example, that certain ne chemicals such as kojic acid could potentially be produced from this source. 6 New enzymes, more suitable for industrial scale, are currently being developed and are likely to open the door for broader utilization of D-glucosone. 6 Established methods exist already for producing various value-added chemicals, including furfurals, from D-fructose.…”

“…6 New enzymes, more suitable for industrial scale, are currently being developed and are likely to open the door for broader utilization of D-glucosone. 6 Established methods exist already for producing various value-added chemicals, including furfurals, from D-fructose. 9,10 The well-known base-catalyzed isomerization of D-glucose to Dfructose is performed in aqueous solutions using both homoand heterogeneous catalysts.…”