富铬酵母发酵条件优化的研究

 利用酵母菌具有较强的富集微量元素的特性，试验对产朊假丝酵母富集微量元素铬的条件进行了优化。从6株酵母菌中筛选出耐铬能力和富集铬能力均较强的CJ2作为试验菌株。试验结果表明：500 mL三角瓶中装入75 mL发酵培养基，采用一次性加铬的方式，适宜的CrCl₃·6H₂O浓度为50 μg/mL，pH值为5.5，接种量为6%，摇床转速180 r/min，28~30 ℃下培养24 h，获得的富铬酵母生物量能达到1.30 g/100 mL，铬含量能达到2 000 μg/g左右，转化率能达到50%左右。同时CJ2菌株发酵罐培养，铬酵母生物量能达到1.80 g/100 mL，铬含量能达到2 500 μg/g左右。并对普通酵母和富铬酵母中的氨基酸组成了分析。

Optimizing the Fermentation Conditions of Chromium-enriched Yeast

Taking advantage of rich trace elements in the yeast,the experiment optimized the conditions of Candida utilis chromium-enriched.Select CJ2 with strong chromium-resistant and chromium-rich ability from six yeasts as a pilot.The cultural conditions were optimized as follows:cultural temperature 28~30℃,rotation 180 r/min,50 μg/mL CrCl3·6H2,amount of medium 75 mL/500 mL flask,inoculums 6%(v/v),initial pH 5.5,culture time 24 h.Under the optimized conditions,the biomass of chromium-enriched yeast,chromium content and conversion were 1.30 g/100mL,2 000 μg/g and 50%,respectively.The CJ2 strains were cultured by using a constant pH value of fermentation in the fermentor.The biomass and chromium content were 1.80 g/100 mL,and about 2 500 μg/g.The amino acid compositions of control yeast and chromium-enriched yeast were analyzed.