光合细菌P4株的反硝化作用

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，并在反硝化作用下测定到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１００％，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，当光照度度达５ｋｌｘ以上时，Ｐ４株反硝化作用非常弱，它的ＮＯ＾－３比肖耗速率ＰＮＯ＾－３仅为黑暗条件下１／１０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

Denitration of Photosynthetic Bacteria P4 Strain

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.