| Chromium (Cr) is an important industrial raw material and widely used in steel, tannage, printing and dyeing, and other fields. Cr(Ⅵ) pollution has become one of the major heavy metal pollutions in China. YEM001 is a group of microbial group that can effectively reduce Cr(Ⅵ) in sludge and landfill leachate to achieve Cr(Ⅵ) pollution bioremediation. However, the expansion of bacterial culture has become an obstacle to further apply YEM001. As a goal to optimize the culture conditions of YEM001, the medium and fermentation conditions of YEM001 were optimized by single factor experiment and orthogonal experiment. The results showed that YEM001 could achieve rapid and stable growth with starch as carbon source. The optimized YEM001 bacterial group culture medium was as follows: starch 10 g/L, ammonium chloride 3 g/L, magnesium sulfate 2 g/L, and yeast extract powder 1 g/L. Through the regulation of stirring speed, pH and ventilation, the optimal fermentation conditions were obtained as follows:28 ℃, pH 7.5, no air pumping, and stirring speed at 50 r/min. Under this condition, the OD600 of YEM001 culture medium could reach as high as 1.91, and 100 mg/L Cr(Ⅵ) could be completely reduced within 60 h. Through cost analysis,the price of each 100 L medium was reduced by 38.11 yuan, which was 51.85% lower than before the optimization. |
