产碱杆菌在水产养殖体系中的分布及其异养氨氧化特性

Distribution and heterotrophic ammonia-oxidizing characteristics of Alcaligenes sp. in aquaculture systems

摘要:

【背景】随着水产养殖集约化程度的不断提高，养殖水体环境中氮素污染及富营养化问题日益加剧，严重抑制自养型氨氧化菌的功能活性，因此深入解析产碱杆菌这类潜在的异养型氨氧化功能微生物在水产养殖系统中的分布特点及其氨氧化功能特性对于解决氮素污染问题具有重要意义。【目的】调查研究水产养殖区域中产碱杆菌的分布情况，分离选育具有高效氮转化能力的产碱杆菌(Alcaligenes sp.)，明确其氨氧化功能特性，为养殖尾水高效脱氮提供菌种资源和理论指导。【方法】通过16S rRNA基因高通量测序技术分析产碱杆菌在广东沿海四大水产养殖主产区中的分布情况，并从养殖鱼塘底泥样品中分离获得一株具有较强异养氨氧化能力的产碱杆菌CHO6，采用单因素分析法，探究菌株CHO6的异养氨氧化特性及其关键影响因素。【结果】广东沿海四大水产养殖主产区中广泛分布着产碱杆菌；从广州市养殖鱼塘底泥样品中分离得到的产碱杆菌CHO6能够在48 h内将10 mmol/L氨氮完全去除，其氨氧化能力优异且受到碳源、温度、pH、C/N、溶解氧、初始氨氮浓度等因素的影响。【结论】产碱杆菌的普遍存在表明其对水产养殖环境具有较强的适应性，产碱杆菌CHO6具有较强的氨氧化能力，能够耐受较高浓度的氨氮，可为水产养殖水体中的氮素去除提供功能菌种资源支持，对水产养殖尾水治理具有重要意义。

关键词:水产养殖;异养氨氧化;产碱杆菌;16S rRNA基因高通量测序

Abstract:

[Background] As the intensification in aquaculture keeps increasing, nitrogen pollution and eutrophication in aquaculture water have become increasingly serious, which inhibit the activity of autotrophic ammonia-oxidizing bacteria. Therefore, it is of great significance to understand the distribution and functional characteristics of heterotrophic ammonia-oxidizing microorganisms such as Alcaligenes sp. in aquaculture systems to address nitrogen pollution. [Objective] We studied the distribution of Alcaligenes sp. in aquaculture areas, isolated the strain with efficient nitrogen conversion ability, and characterized the ammonia oxidation of the strain screened out, aiming to provide strain resources and theoretical guidance for the efficient nitrogen removal from aquaculture tail water. [Methods] The high-throughput sequencing of the 16S rRNA gene was employed to reveal the distribution of Alcaligenes sp. in the aquaculture areas in Guangdong. Alcaligenes sp. strain CHO6 with strong heterotrophic ammonia-oxidizing capacity was isolated from an aquaculture sediment sample by continuous enrichment culture. The single factor tests were carried out to explore the factors influencing the heterotrophic ammonia-oxidizing capacity of the strain CHO6. [Results] Alcaligenes sp. widely existed in the aquaculture areas in Guangdong. Alcaligenes sp. CHO6 isolated from an aquaculture sediment sample completely removed 10 mmol/L ammonia nitrogen within 48 h. The ammonia-oxidizing capacity of the strain CHO6 was influenced by a variety of factors including carbon source, temperature, pH, C/N ratio, dissolved oxygen, and initial ammonia nitrogen. [Conclusion] The prevalence of Alcaligenes sp. indicates strong adaptability to the aquaculture environment. Alcaligenes sp. CHO6 as a heterotrophic strain had strong ammonia-oxidizing capacity and resistance to high concentrations of ammonia nitrogen. This study provides strain resources for the removal of nitrogen in aquaculture environments, which is of great significance for the management of aquaculture tail water.

Key words:aquaculture;heterotrophic ammonia oxidation;Alcaligenes sp.;high-throughput sequencing of the 16S rRNA gene