Fermentative Production of Erythritol from Cane Molasses Using Candida magnoliae: Media Optimization, Purification, and Characterization

Erythritol is a natural, zero-calorie sweetener that can be used as a sugar substitute and humectant for different products such as confectionaries, tablets, etc. Methods such as extraction and chemical synthesis for erythritol synthesis are not feasible or sustainable due to lower yield and higher operating costs. In the present study, erythritol is produced through the submerged fermentation of cane molasses, a by-product of the cane sugar industry, in the presence of the osmophilic yeast Candida magnoliae. Erythrose reductase enzyme assay was used for quantifying erythritol yield. Plackett-Burman's design screened the three most influential factors viz. molasses, yeast extract, and KH2PO4 out of 12 contributing factors. Further, the concentration of molasses (200-300 g/L), yeast extract (9-12 g/L), and KH2PO4 (2-5 g/L) were optimized using response surface methodology coupled with numerical optimization. The optimized erythritol yield (99.54 g center dot L-1) was obtained when the media consisted of 273.96 g center dot L-1 molasses, 10.25 g center dot L-1 yeast extract, and 3.28 g center dot L-1 KH2PO4 in the medium. After purification, the liquid chromatography-mass spectrometry (LC-MS) analysis of erythritol crystals from this optimized fermentation condition showed 94% purity. Glycerol was produced as the side product (5.4%) followed by a trace amount of sucrose and mannitol. The molecular masses of the erythritol were determined through mass spectrometry by comparing [M + Na] + ions. Analysis in electrospray (ES) positive mode gave (m/z) of 145.12 [M + 23]. This study has reported a higher erythritol yield from molasses and used osmotolerant yeast Candida magnoliae to assimilate the sucrose from molasses.

Automated summary

In this study, high yield of erythritol was produced through submerged fermentation using osmotolerant yeast Candida magnoliae in molasses. The fermentation conditions were optimized using experimental design and response surface methodology, resulting in high purity erythritol crystals.