Abstract

Chromium-enriched brewer’s yeast which contains chromium(III) as an essential trace element and cofactor for insulin has important biological functions in metabolism. We investigated its manufacture using chromiumcontaining leather waste from Chinese leather factories. Orthogonal experiments lead us to the optimal shaking culture medium for producing the high chromium content of chromium-enriched brewer’s yeast. The optimum culture medium was: glucose 7g.L-1, (NH4)2SO4 5g.L-1, and Cr3+ containing hydrolysates (mass concentration) 145mg.L-1 The optimal shaking culture conditions were: shaking culture temperature 28°C, 10% inoculum content, pH5.0, rotating speed and time of shaking culture 3.5r/s, 36 hours, respectively, and volume ratio of medium 1:10. The chromium(III) content of the chromium-enriched brewer’s yeast prepared at these optimal conditions was 1337mg/g. The experiments showed that the manufacture of chromium-enriched brewer’s yeast from chromium-containing leather waste is feasible.