(655d) Strategies for Enhancing Glycerol Production in Yeast

Glycerol is a simple polyol compound. It is also called as propane-1, 2, 3-triol (IUPAC) and commercially known as glycerin. Glycerol is widely used in many consumer products, i.e. it is a supplement in pharmaceutical and cosmetic products. In addition, glycerol can be used as a substrate to produce many high-value substances, for example, 1,3-propanediol, epichlorohydrin, acrolein, glycerol carbonate (GC) and glycidol. Glycerol is currently produced via chemical synthesis as the major byproduct from biodiesel production process. However, this route seems unsustainable because the chemical process is not only ecological friendly, but the emerging electric vehicle technology somehow turns down the biodiesel business resulting in the limited supply of glycerol from this route. As the matter of fact, glycerol production from fermentation process has attracted more interest as an alternative process. The challenge for the biotechnologist is to apply the fundamental knowledge on glycerol metabolism to develop an appropriate process for economically converting biobased feedstocks to glycerol by microbial fermentation. To date, yeast fermentation has been extensively applied as the biotechnological platform for glycerol production. Those platforms included sulfite process, alkali process, and osmotolerant yeast process which yielded the final glycerol concentration of 30-40 g/L, 30-40 g/L, and 110-130 g/L, respectively. From the previous literatures, osmotolerant yeast process yielded up to 130 g/L final concentration with the yield up to 63% and the productivity up to 1.67 g/L×h. Therefore, screening for the yeast that acquires the osmotolerant activity becomes of interest. In addition, process optimization for glycerol production by osmotolerant yeast should be developed. In our research group, we have screened and preliminary identified the yeast isolates from the tropical fruits and found that they possessed the ability to produce glycerol from mono sugars. Process optimization was also conducted to improve the glycerol production performance.