【摘要】 将双齿围沙蚕Perineries aibuhitensisG rube放养在闭合循环养殖系统中进行了两轮试验。第一轮试验,沙蚕的放养密度为1049条/m2,设投饵量分别为其体重的20%和10%,记为A、B组。当生物膜成熟后,从A、B系统中分离纯化获得15株细菌,测得异养细菌纯菌株（8株）的耗氧速率为（10.88±0.73）^{114.98±50.62}g O2/（mg蛋白.d）,其中H3菌株的活性最高,为（114.98±50.62）g O2/（mg蛋白.d）;氨化细菌纯菌株（7株）的氨化速率为（0.76±0.57）^1.47±1.09g N/（mg蛋白.d）,各菌株活性接近。同时对生物膜进行了扫描电镜观察,其细菌形态较为多样。第二轮试验,设置沙蚕的放养密度为833、641条/m2,投饵量为其体重的5%,分别记为C、D组。用PC、MPN测定了C、D养殖系统生物膜形成过程中和成熟后异养细菌、氨化细菌和氨氧化细菌的数量变化,同时测定了其代谢活性。结果表明,系统中生物膜形成期间,细菌数量不断增加,异养细菌数量级由105增加到107,氨化细菌数量级C系统由106增加到108,D系统由104增加到106,成熟后细菌数量基本保持稳定。氨氧化细菌数量成熟期间逐渐增加,达到最高值后,随距离投饵时间的延长,又有所下降。异养细菌的耗氧速率、氨化细菌的氨化速率与其数量的变化趋势基本吻合。底物浓度、温度和pH对氨化细菌的代谢活性有明显的影响,当蛋白胨浓度从100 mg/L增加到2000mg/L,温度由10℃增加到35℃,pH由6.5增加到pH 8.5时,氨化细菌的氨化速率呈增加的趋势。更多还原

【Abstract】 Two rounds experiments were designed with four close-recirculating culture systems （A,B and C,D ）of Neries （Perineries aibuhitensis Grube ）according to the density (worms /m²) and feeding rate: 1049 and 20% （A）, 1049 and 10%（B）, 833 and 5% （C）, and 641 and 5%（D）, respectively. In the first round experiment, 15 strains of bacteria were isolated from the biofilms associated with sands in system A, and system B after maturation of biofilm. The oxygen uptake rates of heterotrophic bacteria isolates（eight strains） were （10.88±0.73）-（114.98 ±50.62）g/（mg protein·d）, of which H3 was the highest. The ammonification rates of ammonifier isolates（seven strains） were （0.76±0.57）-（1.47±1.09）g/（mg protein·d）,and the activities of each isolate were similar. Meantime the biofilms associated with sands were observed by scanning electron microscope. The various shapes of bacteria were found. In the second round experiment, the numbers of heterotrophic bacteria, ammonifiers and ammonia oxidizing bacteria in system C, and system D were counted using PC, MPN methods, and their metabolic activities were determined during the forming and maturing periods of biofilm associated with sand in biological filter. The results show that the numbers of three physiological groups of bacteria increased gradually with the forming of biolfilm: the number of heterotrophic bacteria was 10⁵-10⁷CFU/mL （wet sand ）, the numbers of ammonifiers in system C and system D were 10⁶-10⁸ CFU/mL（wet sand ） and 10⁴-10⁶ CFU/mL （wet sand ）,respectively, and both kept stable after maturation of biofilm. The number of ammonia oxidizing bacteria first increased to the maximum, then decreased slightly with the long period after being fed. The changing trends of oxygen uptake rates of heterotrophic bacteria and ammonification rates of ammonifiers were similar to those of numbers of bacteria.The influences of substrate concentrations, temperature and pH on ammonification rates of ammonifiers were observed, when peptone concentrations was within the range of 100-2 000 mg/L, temperature 10-30℃, and pH 6.5-8.5. Ammonification rates of ammonifiers increased gradually.更多还原