响应面法优化细菌EHB01对铜绿微囊藻(Microcystis aeruginosa)的溶藻条件

【背景】水体富营养化导致的蓝藻水华对淡水资源造成了严重污染。利用环境友好型的溶藻菌可有效控制蓝藻的生长,是防治蓝藻水华形成的有效途径之一。【目的】优化溶藻细菌EHB01对铜绿微囊藻(Microcystis aeruginosa)的溶藻条件,以期为治理蓝藻水华污染提供高效的溶藻菌制剂。【方法】采用单因素试验对溶藻的发酵液浓度、温度、光照以及C:N和N:P进行分析,并对溶藻细菌EHB01发酵液的碳源、氮源和p H进行优化。基于单因素试验,选用中心组合试验设计(central composite design,CCD)确定关键因子的最佳数量水平,并以Desig-Expert 8.0.5进行回归分析,通过响应面分析获得溶藻效果最佳的参数。【结果】发酵液浓度对溶藻率的影响表现为持续上升;温度对溶藻率表现为先上升后下降;而光照、C:N和N:P均对细菌EHB01发酵液溶藻率的影响表现为先降低后上升的趋势。溶藻细菌EHB01发酵液所需的最佳碳源为蔗糖,氮源为硝酸钾,pH为7.5,优化条件下溶藻率达86.97%,与优化之前相比提高了21.72%。【结论】采用响应面法优化得出溶藻细菌EHB01发酵液最优的培养条件,且模型拟合效果较好,可为溶藻菌制剂工业化发酵提供有效依据。

Optimization of alginolytic conditions of Microcystis aeruginosa by bacteria EHB01 using response surface methodology

Background] Cyanobacterial bloom caused by eutrophication has caused serious pollution to freshwater resources. The use of environmentally friendly alginolytic bacteria can effectively control the growth of cyanobacteria, which is one of the effective ways to prevent and control the formation of cyanobacteria bloom. Objective] To optimize the alginolytic conditions of Microcystis aeruginosa by bacteria EHB01, so as to produce alginolytic agents for controlling the pollution of cyanobacterial bloom. Methods] The concentration, temperature, light, C:N and N:P of alginolytic fermentation broth were analyzed by single factor test, and the carbon source, nitrogen source and pH of alginolytic bacteria EHB01 fermentation broth were optimized. Based on single factor test, the optimal quantity levels of key factors were determined by central composite design (CCD), and regression analysis was conducted by Desig-Expert 8.0.5. The parameters with the best alginolytic effect were obtained by response surface methodology (RSM). Results] The effect of fermentation liquid concentration on the algicidal ratio was increasing continuously. The effect of temperature on the algicidal ratio was first increased and then decreased. However, the effects of light, C:N and N:P on the algicidal ratio of bacteria EHB01 fermentation broth showed a tendency of decreasing first and then increasing. The best carbon source for EHB01 fermentation liquid was sucrose, nitrogen source was potassium nitrate and pH was 7.5. Under the optimized conditions, the algicidal ratio was up to 86.97%, which was 21.72% higher than before optimization. Conclusion] RSM was used to optimize the optimal culture conditions of alginolytic bacteria EHB01 fermentation broth, and the model fitting effect was good, which could provide an effective basis for industrial preparation of alginolytic agent.