响应面法优化黑曲霉HQ-1产纤维素酶固体发酵条件

Optimization of solid-state fermentation conditions of cellulase produced by Aspergillus niger HQ-1 with response surface methodology

采用单因素试验和响应面法对黑曲霉(Aspergillus niger)HQ-1产纤维素酶的固体发酵条件进行了优化并以滤纸酶活力作为响应值。首先通过单因素试验确定最适碳源为玉米秸秆粉/麦麸(1/1)及其最适含量为12.0g;最适氮源为(NH4)2SO4及其最适含量为1.5g。再利用Plackett-Burman设计筛选出影响滤纸酶活力的显著因素:含水量、培养温度和起始pH值。通过最陡爬坡试验逼近最大酶活力区域。最后用Box-Behnken设计及响应面分析确定产酶的最佳发酵条件为玉米秸秆粉6.0g、麦麸6.0g、(NH4)2SO4 1.5g、KH2PO41.6g、MgSO4.7H2O 0.8g、含水量73.5%、起始pH值为3.91、培养温度和培养时间分别为33.9℃和96h。经过优化,滤纸酶活力最高为59.432U/g,比未优化的酶活力最高值(13.511U/g)提高了3.40倍。

Using filter paper activity （FPA） as the response value, single-factor tests and response surface methodology （RSM） were used to optimize solid-state fermentation（SSF）conditions for cellulase production by Aspergillus niger HQ-1. Single-factor test was first adopted to determine the optimal carbon source and nitrogen source. Carbon source were corn stalk powder and wheat bran （12.0g, 1：1）, and nitrogen source was （NH4）2SO4 （1.5g）. Plackett-Burman design（PBD）was further adopted to screen the important factors affecting FPA, including moisture content, cultivation temperature and initial pH value. The steepest ascent experiment was used to approach the optimal region of FPA. The optimal fermentation conditions were obtained by Box-Behnken design（BBD）and response surface analysis as follows： corn stalk powder 6.0g, wheat bran 6.0g, （NI-L）2SO4 1.5g, KH2PO4 1.6g, MgSO4·7H2O 0.8g, moisture content 73.5%, initial pH value 3.91, culture temperature 33.9℃ and culture time 96h. Under these conditions, FPA reached 59.432U/g, which was increased by 3.40 folds compared with that （13.511U/g） before optimization.