Isolation and identification of a novel Candida sp. H2 producing D-arabitol and optimization of D-arabitol production.

To isolate a new osmophilic yeast for producing D-arabitol and research its optimal fermentation conditions for highest yield of D-arabitol from glucose. The isolated strain was characterized by electron microscopy, Biolog (GN) test, G + C content measurement and 26S rDNA D1/D2 domain sequences analysis. The purified fermentation product was identified by IR, 1H-NMR, 13C-NMR, MS and optical rotation analysis. Then the fermentation conditions for D-arabitol production were optimized. A new osmophilic yeast was isolated and identified as Candida sp. H2. Through the single factor experiment,the optimum conditions of 250 g/L glucose,10 g/L yeast extract, initial pH 6.0, 35 degrees C of culture temperature, 200 r/min of agitation, 200 mL medium in a 1000 mL flask of broth content, 1% (v/v) of inoculum size, 96 h of fermentation time were achieved. Based on the conditions above,weight yield of 35% (86.55 g D-arabitol from 250 g glucose) was obtained and 10% higher than the conditions not optimized. Candida sp. H2 was a novel strain for producing D-arabitol and valuable for further study.