摘要
光合细菌 P4株在厌氧条件下 ,具有反硝化活性 ,在好氧条件下 ,这种活性受到抑制 .但 P4不能利用硝酸盐作为氮源同化为自身细胞物质 ,并在反硝化作用中测定到 N2 的存在 ,说明 P4株反硝化作用是通过异化途径实现的 .不同碳源对 P4株反硝化作用具有不同的协同性 ,特别以苹果酸钠、乙酸钠等为碳源时 ,P4株对硝酸盐去除率接近 1 0 0 % .在黑暗厌氧条件下 ,P4株主要通过反硝化作用获得能量而生长繁殖 .在光照厌氧条件下 ,P4株可以通过光合成作用 (光合异养 )和反硝化作用获得能量生长繁殖 .但两者是竞争性的 ,即负相关性 .当光照度达 5klx以上时 ,P4株反硝化作用非常弱 ,它的 NO-3 比消耗速率 RNO-3 仅为黑暗条件下 1 /1 0左右 .不管是在光照或黑暗条件下 ,亚硝酸盐在低浓度范围内 ,P4株对亚硝酸盐也有良好还原活性 ,其中最适碳源为苹果酸钠、乙酸钠、琥珀酸钠等 ,亚硝酸去除率达 82 .6%～ 99.8% .但亚硝酸盐对 P4株有毒性作用 ,当达到 1 mmol/L时 ,P4株色素合成明显受到影响 ,达到 4 mmol/L,P4株生长严重受到抑制 .
Photosynthetic bacteria P 4 strain has an activity of denitration under the anaerobic condition. The activity can be repressed under the aerobic condition. P 4 can not utilize nitrate as the nitrogen source in its assimilation. Since nitrogen can be detected in its denitrifying process, the denitration of P 4 must be implemented by its dissimilation. Different carbon sources show different cooperative functions in the denitration. P 4 can remove nearly 100% nitrate by using malate or acetate as carbon sources. P 4 mainly get energy through denitration under the dark anaerobic condition. Hwoever, P 4 can get energy through both photosynthesis and denitration under the light anaerobic condition. But the two ways are competitive. When the light illumination is larger than 5 klx, the denitration is very weak. The specific rate of the nitrate consumption is only 1/10 as fast as that under the dark anaerobic condition. In the range of low concentration of nitrite, P 4 has a good activity of reducing nitrite no matter light or dark condition. Malate, acetate, succinate are optimal carbon sources for P 4 reducing nitrite. Removal rates of nitrite are from 82.6% to 99.8%. But nitrite is toxic for P 4. When the concentration of nitrite reaches 1 mmol/L, the pigment synthesis of P 4 is obviously affected. When it reaches 4 mmol/L, the growth of P 4 is seriously inhibited.
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
2000年第11期1579-1582,1597,共5页
Journal of Shanghai Jiaotong University
基金
:上海市科委发展基金
