Microbial production of D-mannitol and D-fructose from glycerol

In view of the recent development that some petrochemical products are efficiently available as substrates for the fermentation industry, glycerol manufactured from propylene by chemical synthesis would also be hoped for the purpose. This paper describes some of the factors influencing mannitol production from glycerol by Torulopsis yeasts and a microbial conversion of glycerol to D -fructose via mannitol, in which two sequential steps of yeast and Acetobacter fermentation are involved. Torulopsis mannitofaciens CBS 5981 and Torulopsis vcrsatilis CBS 1752, exceptionally good mannitol producers, were selected for the study. High concentrations of nitrogen sources and KH₂PO₄ in the medium markedly decreased mannitol yield in spite of good utilization of the substrate. T. mannitofaciens produced mannitol in yield of 31% of the glycerol consumed at optimal condition. The fermentation by washed yeast cells gave much higher mannitol yield of more than 50%. A sequential fermentation process was carried out without isolation and purification of the intermediate and yielded.51.7%. D -fructose from the glycerol.