地热水中一株好氧反硝化菌的分离鉴定及最优反硝化条件的研究

Isolation,identification and denitrification optimization of an aerobic denitrifying bacterium from geothermal water

从开封市某酒店1 200m深地热井中抽取地热水,筛选到1株较高效的好氧反硝化菌A1。对A1进行16SrRNA基因序列测定,确定A1为地衣芽孢杆菌（Bacillus licheniformis）。A1在40h内对硝态氮和TN的去除率分别为96.10%、90.60%。相比亚硝态氮,A1更容易利用硝态氮进行反硝化作用。相比甲醇,琥珀酸钠和柠檬酸钠更适合作为A1的碳源;初始pH对A1的生长量和脱氮效率影响显著,最适初始pH为7.5;A1在25~50℃下均生长良好,并保持较高的脱氮效率,但最适温度为35℃;溶解氧浓度既能影响A1的生长量和硝态氮去除率,还能影响亚硝态氮的积累量,静置培养时,虽然A1生长量不高,但是硝态氮去除率达到90.22%。可见,A1为耐高温的兼性好氧菌。

An aerobic denitrifying bacterium,named Al,was isolated from 1 200 m depth geothermal water of a hotel in Kaifeng, Henan. A1 was identified as Bacillus licheniformis through 16S rRNA gene sequence test. The re- moval rates of nitrate nitrogen and TN in 40 h were 96.10% and 90.60% ,respectively. Compared with nitrite nitro- gen,nitrate nitrogen was more suitable to ultilize for denitrification progress.The optimal carbon resources were sodium succinate and sodium citrate rahter than methanol. The initial pH impacted the growth and nitrogen removal rates of A1 obviously,with the optimum initial pH 7.5. Al experienced a normal growth and maintained relative high nitrogen removal rates at 25-50 ℃. However,the optimum temperature was 35 ℃. Dissolved oxygen concentrations influenced the growth and nitrogen removal rates of A1 ,as well as the accumulation of nitrite nitrogen. When stewing cultured,the growth of A1 was not high,but the removal rate of nitrate nitrogen reached 90.22%. Thus,A1 was a faeul- tative aerobic bacteria and bearable to high temperature.