十二烷基硫酸钠降解菌株Pseudomonas sp. SDS-2的降解能力及其低温降解活性的调控（英文）

Sodium dodecyl sulfate degradation performance of Pseudomonas sp. SDS-2 and its activity regulation at low temperatures

尽管生物法已广泛用于表面活性剂废水的处理,但低温对微生物的代谢活性产生明显不利影响,导致出水难以稳定达标.对筛选到的十二烷基硫酸钠(SDS)降解菌的降解能力进行考察,并对不同调控策略作用下该菌株的低温降解活性进行评估.对筛选到的菌株进行16S rRNA基因序列测定与分析.该菌株在不同温度、pH、底物浓度、接种量下的降解能力以及不同调控策略(低温驯化、外源物质添加)下的低温降解活性均以化学需氧量(COD)的去除率间接表示.结果筛选到一株SDS降解菌,命名为SDS-2. 16S rRNA基因序列分析表明该菌株属于假单胞菌属(Pseudomonas sp.).该菌株的最佳生长条件为30℃、pH 9和120 mg/L氨浓度,而接种量对其降解活性无明显促进作用.当SDS初始浓度为2 500 mg/L时,该菌株对SDS的去除速率(以COD计)可达到355.3 mg L^(-1) h^(-1). 15℃下,长期驯化可使该菌株的降解活性达到30℃时的水平;10℃下,添加外源物质丁二酸钠和硝酸钾可使COD的去除率在48 h内分别提高25.3%和24.6%;外加蛋白胨和复合维生素可使COD的去除率在24 h内分别提高22.8%和11.7%.本研究筛选到的Pseudomonassp.SDS-2具有高的SDS降解活性,可为实际含SDS表面活性剂废水的处理提供微生物资源;同时,本研究中的调控策略亦可为SDS低温生物处理提供潜在处理方法.

Biological methods have been widely used for surfactant removal;however, low temperatures always exert adverse effects on the metabolic activity of microorganisms. In this study, we investigated the optimum growth conditions for a sodium dodecyl sulfate(SDS)-degrading strain and evaluated its low-temperature degradation activity with different regulation strategies. The SDS-degrading strain screened in this study was identified using the 16 S rRNA gene sequencing method. The degradation performance of the strain was evaluated under different temperatures, pH values, substrate concentrations, and inoculum sizes. Furthermore, the metabolic activities of the strain under different regulation strategies(acclimation and extra substance addition) at low temperatures were indirectly evaluated by chemical oxygen demand(COD) removal efficiency.The SDS-degrading strain was isolated and identified as Pseudomonas sp. SDS-2. The optimum growth conditions for the SDS-2 strain were 30 ℃, pH 9, and 120 mg/L ammonia concentration. The inoculum size showed no obvious effects on SDS degradation. The COD removal rate was as high as 355.3 mg L-1 h-1 when the initial SDS concentration reached 2 500 mg/L.After long-term acclimation at 15 ℃, the substrate removal efficiency at 15 ℃ reached the same level as that at 30 ℃. At 10℃, the substrate removal efficiencies were increased by 25.3% and 24.6% at 48 h with sodium succinate and potassium nitrate addition, respectively. Furthermore, the substrate removal increased by 22.8% and 11.5% at 24 h with the addition of peptone and multi-vitamins, respectively. The high SDS-degrading activity of the strain SDS-2 shows that it can be used as a microbial resource for actual SDS-containing wastewater treatment, and the regulation strategies applied in this study can be used as potential methods for SDS remediation at low temperatures.