Community structure and denitrification ability of aerobic and anaerobic denitrifying bacteria from mangrove wetland
红树林湿地中好氧-厌氧反硝化菌脱氮特性及其种群结构分析

Mangrove wetlands dominate the coastline of tropical and subtropical regions. With the expansion of human activity along riverine and coastal shorelines,mangroves are subject to anthropogenic inputs,which introduce additional nitrogen to mangrove ecosystems. In the present study,both traditional cultivation and molecular method(clone library and RFLP) were used to investigate the community structure and abilities of denitrifying microorganism from Mai Po mangrove sediment. Twenty aerobic and anaerobic denitrifying bacteria strains were obtained and most of them had the abilities to remove 98% NO-3-N in 2 days. The aerobic denitrifying bacterial strains belonged to the genera of Pseudomonas,Comamonas and Acinetobacter. The anaerobic denitrifying bacterial strains were Pseudomonas,Agrobacterium,Uncultured Betaproteobacteria bacterium. To investigate the diversity of denitrifying bacteria in the mangrove sediments,nosZ gene clone library were constructed. 26 out of 50 clones belonged to 11 unknown groups,while the others were the Pennisetum(26%) ,the β-proteobacterium(10%) ,the Entandrophragma(4%) ,the Pseudomonas(4%) and the denitrifying bacterium(4%) . This indicated that Mai Po mangrove had high degree of taxonomic diversity of denitrifiers.