Optimization of D-ribose production with a transketolase-affected Bacillus subtilis mutant strain in glucose and gluconic acid-based media

Abstract

When the transketolase‐deficient and D‐ribose‐producing Bacillussubtilis strain ATCC 21951 was grown in a glucose (200 g l−1)‐based medium (Kintaka et al. 1986), only 11 g l−1D‐ribose was synthesized, in addition to acetic acid (12 g l−1) and acetoin plus 2,3‐butanediol (24 g l−1), within 1 week of fermentation. After optimizing the process conditions at 2 l fermentor scale (simplified medium composition, pH 5·0 or 6·0, highly oxidative (1000 rev min−1, 3 vvm)), 40 g l−1D‐ribose was obtained from 200 g l−1D‐glucose, in addition to 14·5 g l−1 acetoin, during 1 week of fermentation. By partially substituting D‐glucose with D‐gluconic acid (100 g l−1D‐glucose plus 50 g l−1D‐gluconic acid) under highly oxidative (1000 rev min−1, 3 vvm) and pH‐controlled (pH 6·5) conditions, D‐ribose productivity increased (45 g l−1) and acetoin formation (7·5 g l−1) dropped, as did the fermentation time (3·5 d). The mixed carbon substrate procedure here developed provides an excellent alternative to the less efficient glucose‐based processes described so far.

Enhanced d-ribose biosynthesis in batch culture of a transketolase-deficient Bacillus subtilis strain by citrate

“…Glucose and corn steep liquor are particularly effective for production of D-ribose [9,32]. To increase D-ribose production, some substrates metabolized only via the pentose phosphate pathway, such as D-gluconic acid, D-xylose, D-xylitol, and D-arabinose, were supplied together with glucose [7,10,28,29]. For example, 50 g l -1 of D-gluconic acid were supplied together with 100 g l -1 of D-glucose to obtain 45 g l -1 of D-ribose in 84 h [10], and the yield of D-ribose was increased from 0.24 to 0.37 mol mol -1 based on total carbon sources consumed.…”

Megacell phenotype and its relation to metabolic alterations in transketolase deficient strain of Bacillus pumilus

“…D-Ribose also finds applications in treatment of myocardiac ischemia and certain rare genetic disorders (Gross et al, 1991;Zimmer, 1992;Zimmer et al, 1984). Methods based on chemical or chemo-enzymatic synthesis or fermentation process have been reported for D-ribose production (Bredereck and Rothe, 1938;DeWulf et al, 1997a;Gehrke and Aichner, 1927). However, only the fermentation-based methods have been found to be commercially viable.…”

Combined effects of carbon, nitrogen and phosphorus substrates on D‐ribose production via transketolase deficient strain of Bacillus pumilus

“…1 By partial substitution of D-glucose with D-gluconic acid and by optimizing the process conditions, such as maintaining the pH and highly oxidative conditions, D-ribose productivity was shown to increase four-fold while acetoin concentration decreased two-fold. 9 An independent study has shown improvement in D-ribose productivity by twofold in a fed batch process using a mixture of xylose and glucose with a strain of Bacillus subtilis SPK1. 12 However, the effect of nitrogen substrate on D-ribose production has not been reported.…”

“…9 Various carbon sources such as D-glucose, D-sorbitol, D-maltose and D-xylose, and nitrogen substrates such as ammonium sulfate, yeast extract, corn steep liquor and soya flour have been shown to be useful for large-scale D-ribose production. 10 Some organic acids such as sorbic acid have also enhanced the D-ribose productivity due to cell metabolism induction.…”