产木聚糖酶菌株YS1069的产酶条件优化

Optimization of the Fermentation Conditions for Xylanase-Producing Strain YS1069

为获得较高的木聚糖酶产量,采用单因素实验和响应面实验方法,筛选氮源、碳源、无机盐、接种量、装液量、Na_2CO_3、发酵温度、发酵时间多个单因素,对产木聚糖酶的芽孢杆菌YS1069的发酵培养基和发酵条件进行了优化。结果显示,豆饼粉25 g/L、麸皮40 g/L、NaNO_3 0.9 g/L、K_2HPO_43 g/L、MgSO_4·7H_2O 0.6 g/L、接种量4%、装液量30 ml/250 ml(v/v)、Na_2CO_3添加量18 g/L、培养温度30℃、培养时间96 h时,酶活性达到最高。再通过Plackett-Burman设计对影响木聚糖酶产量的8个主要因素进行评价,确定Na_2CO_3浓度、麸皮浓度和MgSO_4·7H_2O浓度是影响产酶量的3个主要因素。利用中心组合设计及Design-Expert 8.05软件分析,获得了主要因素的最优条件,即Na_2CO_3浓度21.86 g/L、麸皮浓度51.41 g/L、MgSO_4·7H_2O浓度0.59 g/L,实验最终酶活性比发酵优化前提高了5倍。

In this study we applied one-single factor and response surface method to optimize the culture medium and other conditions for strain YS 1069, which would improve the yield of xylanase. First, the single factor method was used to screen eight factors including the nitrogen source, the carbon source, the inorganic salts, the inoculation volume, the liquid volume, Na2CO3, fermentation temperature and fermentation time. The optimal results corresponding to each single factor was as follows： bean cake powder 25 g/L, wheat bran 40 g/L, NaNO3 0.9 g/L, K2HPO4 3 g/L, MgSO4·TH2O 0.6 g/L, inoculums at 4%, 30 mi/250 ml （v/v） liquid volume, Na2CO3 18 g/L, cultured at 30℃ for 96 h. Secondly, these main variables were evaluated with the Plackett-Burman test. The results suggested that Na2CO3, wheat bran and MgSO4·7H2O were the most impactful factors. Finally, the optimal levels of the three factors were determined with central composite design and Design-Expert 8.05 software. The results were shown as follows： Na2CO3 21.86 g/L, wheat bran 51.41 g/L, and MgSO4·7H2O 0.59 g/L. Under the optimized conditions, the oroduction of xylanase was increased by 5 folds.