解淀粉芽胞杆菌FJAT-8754产纤维素酶和淀粉酶特性及发酵条件优化

采用淀粉平板和羧甲基纤维素钠（CMC-Na）平板从选取的140株芽胞杆菌中初筛出8株具有产纤维素酶和淀粉酶复合酶芽胞杆菌，经酶活力测定解淀粉芽胞杆菌FJAT-8754（Bacillus amyloliquef aciens）具有较高的淀粉酶、纤维素酶活力。通过研究解淀粉芽胞杆菌FJAT-8754的生长、产酶曲线以及酶学特性，确定在发酵28 h后菌体生长进入稳定期，培养44 h时发酵液中活菌数达到最大为4.41×109 cf u · mL -1，在36 h时纤维素酶、淀粉酶均达到酶活最高峰，酶活分别为135.8、1543.3 U · mL -1；纤维素酶反应最适p H值为5.5、最适温度为50℃，Vmax为5.14×10-3 mg · mL -1· min-1、 Km值为7.71×10-1 mg · mL -1；淀粉酶反应最适pH值为5.5、最适温度为55℃，Vmax为3.35×10-2 mg · mL -1· min-1、 Km值为6.03×10-3 mg · mL -1。采用3因素7水平，即U 7（73）均匀设计法优化解淀粉芽胞杆菌产酶条件，确定产纤维素酶、淀粉酶的最优条件均为：初始pH值6.2、培养温度37.5℃、转速180 r · min-1，优化后解淀粉芽胞杆菌 FJAT-8754纤维素酶活力为202.9 U·mL -1、淀粉酶活力为2392.9U·mL -1。

The Characteristics of Cellulase and Amylase from B.amy lolique f aciens FAJT-8754 and Optimization of Fermentation Conditions

Eight Bacillus strains which produce cellulase and amylase were screened from 140 standard Bacillus strains by using starch medium and carboxymethylcellulose sodium （CMC-Na） plate screening method .FJAT-8754 had the highest cellulase and amylase producing activities and the biological characterizes （e .g .growth curves , dynamic changes of enzyme activity and enzymatic properties ） were tested .Our results suggested that the stationary phase of FJAT-8754 was at 28 h ,the colony count was 4.41 × 109 cfu · mL -1 at 44 h and the activity of cellulase and amylase peaked at 36 h simultaneously .Meanwhile ,the optimum reaction conditions for cellulase were at pH 5.5 ,55℃ ,Vmax was 5.14 × 10-3 mg · mL -1 · min-1 and Km was 7.71 × 10-1 mg · mL -1 ;the optimal reaction conditions of amylase were at pH 5.5 ,60℃ ,Vmax was 3.35 × 10-2 mg · mL -1 · min-1 and Km was 6.03 × 10-3 mg · mL -1 .Furthermore ,uniform design assays showed that the optimal submerged culture conditions for cellulase＆amp;nbsp;and amylase was at pH 6.2 ,fermentation temperature was at 37.5℃ ,shaking speed was 180 r · min-1 ,and the activity of cellulase and amylase could reach 202.9 , 2 392.9 U · mL -1 , respectively .