The invention relates to a 
microorganism and a microbial 
fermentation process thereof, in particular to a 
chromium-rich 
yeast culture and a 
fermentation process thereof. The process is characterized by selecting and screening 
Candida tropicalis and 
saccharomyces cerevisiae tolerant of high 
chromium and carrying out production through a liquid-
solid two-phase 
fermentation process. The process flow comprises that: high-
chromium-tolerant (trivalent) strains are screened; the strains are progressively expanded and cultured; liquid fermentation is performed to transform inorganic chromium, wherein the content of the inorganic chromium in a culture medium is 0.05 to 0.4 percent, preferably 0.1 to 0.2 percent, and the time of fermentation and transformation is 12 to 48 hours, preferably 18 to 26hours; after the liquid fermentation is over, culture solution and a 
solid culture medium are mixed according to the weight ratio of 1:3-1.5:1, preferably 1:1, and are subjected to 
solid aerobic fermentation for 16 to 36 hours, preferably 16 to 24 hours; after the solid aerobic fermentation is over, solid anaerobic fermentation is performed to break the wall of 
yeast at a temperature kept between40 and 60 DEG C for 6 to 24 hours, preferably at 50 DEG C for 6 to 10 hours; and a finished product after 
drying contains organic chromium accounting for 0.05 to 0.3 percent. The proportion of transforming the inorganic chromium into the organic chromium by utilizing a technique of the invention is more than 85 percent, and no 
hexavalent chromium is detected. The chromium-rich 
yeast culture produced in the invention has the characteristics of simple process, low production cost, good product quality and the like, has the double function of organic chromium and 
probiotic feed, and can be used for feed of 
livestock, poultry and aquatic products.