响应面分析法优化耐高温假黄色单胞菌硫氧化性能

【目的】采用响应面分析法对耐高温假黄色单胞菌的硫氧化性能进行优化。【方法】利用Plackett-Burman试验筛选影响菌株硫氧化性能的关键因子。通过最陡爬坡试验逼近最佳值区域,确定响应面试验中心轴,利用Box-Behnken设计和响应面分析法获得关键因素的最佳浓度。采用经典的改良硫酸钡比浊法测定硫酸根含量。【结果】牛肉膏、麦芽糖、镁离子(Mg~(2+))3个因素是影响菌株硫氧化性能的关键因素。响应面分析表明牛肉膏和镁离子的交互作用对硫酸根转化率的影响最大,优化后的结果为:麦芽糖(%)=0.07,牛肉膏(%)=0.11,Mg~(2+)(%)=0.04时,模型有最大值。模型的F值为52.60(P0.000 1),相关系数R2=0.980 2,说明该二次方程是显著的,该模型在整个回归区域内的拟合较好。经模拟堆肥试验验证该菌株可以有效增加堆肥中硫酸根含量。【结论】该模型可用于分析和预测耐高温假黄色单胞菌优化培养基配方,经优化后该菌株硫氧化性能大幅提升,硫酸根转化率由36.89%提高到80%以上,加入堆肥后与基础发酵条件下菌液相比更加有效增加了堆肥中SO_4~(2-)的含量,具有较好的应用前景。

Optimization of oxidation by a thermotolerant Pseudoxanthomonas through response surface methodology

Objective] The response surface methodology was used to optimize thermotolerant Pseudoxanthomonas oxidation effect. Methods] We use Plackett-Burman method to select key factors for the sulfur oxidation. The steepest ascent method has been used to determine the optimal range of values and confirm the central axis. Box-Behnken experimental design was used to confirm the optimal concentration of the key factors. The concentration of sulfur was determined by classic barium sulfate turbidity method. Results] Beef extract, malt sugar and Mg2+ were the key factors affecting the sulfur oxidation performance. The results of the response surface methodology showed that the interaction effect between beef extract and Mg2+ had the most effects on sulfate conversion rate. The optimization results were: malt sugar (%)=0.07, beef extract (%)=0.11, Mg2+=0.04, the sulfate conversion rate reached peak value. The F-value of the model was 52.60 (P<0.000 1) and correlation coefficient (R2)=0.980 2 which indicated the model terms were significant and showed good degree of fitting. The simulation composting experiments results showed that the concentration of sulfate in compost increased with Pseudoxanthomonas addition. Conclusion] This model could be used to analyze and calculate the optimal formula of thermotolerant Pseudoxanthomonas culture medium. The sulfur conversion rate increased from 36.89% to over 80% after optimization. Addition of Pseudoxanthomonas in compost could increase sulfate concentration, compared with the suspension culture under basic fermentation conditions, which was of good application prospects.