Title: Alternative Sweeteners

Erythritol 237
The commercial production of erythritol uses a completely biotechnological
process using enzymes and osmophilic yeasts or fungi (2, 13–18). All other
polyols are prepared by the catalytic hydrogenation of a precursor; for example,
xylose from xylan is used to manufacture xylitol. Moniliella, Trigonopsis, or
Torulopsis are some of the microorganisms that can convert glucose to erythritol
in relatively high yields. The basic process is outlined in Fig. 2. Wheat starch
or cornstarch is the usual starting material. These are hydrolyzed primarily to
glucose and other carbohydrates in lower concentration. An inoculum of the osmotolerant
microorganism is added to the substrate, which ferments glucose to
a mixture of erythritol and minor amounts of glycerol and ribitol. One of the
yeasts used, Moniliella, can thrive at high sugar concentration and at the same
time produce erythritol. This characteristic of Moniliella is advantageous because
a concentrated substrate can be used as a starting material, and glucose can be
added continuously to the fermentation tank without adversely affecting the
Figure 2 Commercial production of erythritol.