【作者】 王战勇；

【导师】 陈珊；

【作者基本信息】 东北师范大学 ， 微生物学， 2006， 硕士

【摘要】 向培养基中添加无机铬（CrCl₃·6H₂O）,通过振荡培养制备富铬酵母。考察不同培养条件（包括培养基的种类;培养基中铬的添加浓度;培养基起始pH值;振荡培养时间;酵母添加量;培养温度等）对制备富铬酵母的影响。根据单因素考察结果,以Cr³⁺添加浓度、振荡培养时间、培养基起始pH值及酵母添加量为考察因素,设计一个四因素三水平的正交实验。确定富铬酵母的最佳培养条件如下:采用麦芽汁为培养基;培养温度28℃;Cr³⁺浓度为600μg/mL,培养基起始pH为4.0～4.5,振荡培养时间为18h,啤酒酵母添加量为50g/50mL（培养基）。为进一步了解富铬酵母的富铬机理,采用红外分析法对空白废酵母和富铬酵母进行了红外光谱分析。发现富铬酵母的红外吸收光谱图与空白酵母相比较有两处发生变化。一是羟基的最大吸收位峰从3317cm^-1蓝移至3296cm^-1,这可能是由于部分羟基参与了富集,引起羟基最大峰位置蓝移。二是酰胺Ⅱ带最大吸收峰由1545cm^-1蓝移至1538 cm^-1。这种改变可能是由于酵母菌体上某些蛋白参与了对铬离子的富集。氨基酸组成分析显示富铬酵母中各种氨基酸的含量大多高于未富铬的酵母样品,尤其是赖氨酸、蛋氨酸、亮氨酸、异亮氨酸等人体必需氨基酸的含量明显提高。动物实验显示大鼠对富铬酵母中Cr³⁺的表观消化吸收率为89.03%,且大鼠对富铬酵母这种有机铬形式的吸收率大大高于普通的无机铬盐。更多还原

【Abstract】 Through adding inorganic chromium （CrCl₃·6H₂O） into the culture medium, chromium-enriched yeast was produced by means of shaking culture. Each kind of influence factors on preparation of chromium-enriched yeast （ kind of culture medium, concentration of chromium ion, initial pH of culture medium, cultivate time, yeast adding quantity, cultivate temperature）are studied.According to the result of single factor test, an orthogonal experiment （four factors and three level） was designed, The studied factors are concentration of chromium ion, cultivate time, initial pH of culture medium and yeast adding quantity. The optimum condition is as follows: The wort is chose as culture medium, cultivate temperature is 28℃, The concentration of chromium ion is 600μg/mL, initial pH of culture medium is 4.0 4.5, cultivate time is 18h, yeast adding quantity is 50g/50mL culture medium.In order to find out the chromium-enriched mechanism, the chromium-enriched yeast and blank yeast were analyzed by infrared spectrum （IR）. It is showed that there are two changes in the IR. The first one is that max absorption peak of hydroxyl shifts from 3317cm^-1 to 3296cm^-1. Maybe the hydroxyl involve enrich of chromium. The second one is that max absorption peak of amide （II） shifts from 1545cm^-1 to 1538cm^-1. Maybe some protein in the yeast involve enrich of chromium.The amide acid analysis shows the content of amino acids in chromium enriched yeast was higher than that of general yeast, especially the contents of necessary amino acids, such as lysine, methionine, leucine, isoleucine.Animal experiment shows apparent digestive absorptivity of rat is 89.03%. The digestive absorptivity of chromium enriched yeast, which is organic, by rat is higher than that of inorganic salt.更多还原