亚硝酸钠高效利用菌的分离及其特性研究

Isolation and characterizing of microoganism with high sodium nitrite-utilization character

通过富集培养筛选到6株高效利用亚硝酸钠的细菌和真菌,选择其中一株命名为S1,经初步鉴定为荧光假单胞菌。该菌能以亚硝酸钠为单一氮源生长。生长谱法试验表明,S1能够利用有机碳源物质:甘油、葡萄糖、蔗糖。S1能够利用多数常用的有机氮源物质和无机态氮,以蛋白胨、亚硝酸钠为氮源时生长较好。亚硝酸钠利用试验表明:S1利用亚硝酸钠最适接种菌龄是35 h左右,S1在亚硝酸钠为2 g.L-1时,10%(体积分数)左右的接种量,pH 7.0,28℃,经40 h震荡培养,亚硝酸钠被利用率可达100%。S1菌株的培养需要有较好的通气条件,培养液以装至容器体积的1/5为宜。S1能耐受多种金属离子,Ba2+、Zn2+、A l3+、Cu2+等对其生长和利用亚硝酸钠不造成影响(P>0.05),而Cd2+、Cr3+、Pb2+和Ag+则产生显著抑制作用(P<0.05或P<0.01)。滤膜除菌试验表明S1主要是通过胞外酶的作用利用亚硝酸钠。

By enrichment cultivation, six strains including four bacteria and two fungi, with the character of high sodium nitriteutilization were isolated. One germ, namely S1, with the highest utilization rate was identified as Pseudomonas fluorescens. Auxanographic analysis of its carbon and nitrogen source showed that S1 could use organic carbon source as well as organic and inorganic nitrogen source. Glycerin, glucose and sucrose were the optimal carbon source. Peptone and sodium nitrite were the optimal nitrogen source. S1 showed the highest utilization efficiency of 100 percent to sodium nitrite under the following conditions ： the inoculation age of 35 h, the initiation comcentration of sodium nitrite of 2 g · L^-1, the inoculation quantity of 10%, pH value of 7.0, temperature as 28 ℃, rotation speed of the shaker being 150 r· min^-1 ; the cultivating time of 40 h, and the proper volume of medium/volume of flask being 1/5. S1 could tolerate many metal ions such as Ba^2＋ , Zn^2＋ , Al^3＋ and Cu^2＋ and these metal ions had no influence on its growth and the ability of utilizing nitrite （P 〉 0. 05 ）. However, Cd^2＋ , Cr^3＋, Pb^2＋ and Ag^＋ significantly inhibited its growth and decreased the sodium nitrite-utilization ratio （P 〈0.05 or P 〈0.01 ）. Besides, the exoenzyme was proven to utilizing sodium nitrite by strain S1.