5-Hydroxymethylfurfural production from salt-induced photoautotrophically cultivated Chlorella sorokiniana

Abstract

5-hydroxymethylfurfural (5-HMF), a key precursor to biochemicals has been produced from simple sugars. We report the production of 5-HMF directly from sustainable Chlorella sorokiniana cultivated in a saline medium supplied with CO2 as the sole carbon source. 43% carbohydrate and 16% lipid production in C. sorokiniana were achieved with an optimized CO2 concentration of 1%. 5-HMF yield of 52% was produced in a one-pot acid dehydration reactor at 150 °C in 2 h. 5-HMF yield from C. sorokiniana was almost a 40-fold higher than that from lignocellulose sugar cane bagasse – a highly abundant biomass. SEM images revealed that, the cells of C. sorokiniana could easily be broken in this one-pot reactor to liberate the built-up carbohydrate from the plastids of the cells for subsequent conversion to 5-HMF. The presence of lipids in C. sorokiniana was found to promote the conversion of starch to 5-HMF. Ultimately, the addition of LiCl was found to produce more than 2-fold 5-HMF from C. sorokiniana when compared to the absence of metal salts, with a 5-HMF selectivity of 98.7%. These findings suggest that, starch accumulating microalgae could be potential sustainable feedstock for 5-HMF production.