Screening and mutational improvement of a D-ribose secreting Candida pelliculosa strain

The application of D-ribose in chemistry and pharmacy lately has received much attention. In order to develop an efficient D-ribose production process, a screening strategy was established to isolate naturally occurring D-ribose secreting microorganisms. Of the more than two thousand strains isolated, only four excreted D-ribose in a range from 0.04 to 0.36 g/l, starting from 30 g/l of D-glucose. One strain, identified as Candida pelliculosa, quantitatively co-produced D-arabitol (up to 7 g/l). This strain was subsequently submitted to UV-mutagenesis and a selective nystatin-based enrichment, leading to the isolation of a D-arabitol non-secreting mutant (C. pelliculosa PDW 43 ARA(-)), which synthesized 5 g/l of D-ribose from 30 g/l of D-glucose.