【摘要】：從秸稈還田土壤中初篩獲得一株高效纖維素降解菌CMC-4,根據(jù)菌株形態(tài)、理化性質(zhì)及16S rDNA序列分析,初步鑒定為地衣芽孢桿菌(Bacillus licheniformis)。以此為出發(fā)菌株,經(jīng)亞硝酸鈉誘變獲得一株穩(wěn)定高產(chǎn)纖維素酶突變株CMC-4-3。對(duì)CMC-4和CMC-4-3的產(chǎn)酶條件和酶學(xué)性質(zhì)進(jìn)行比較分析,結(jié)果表明:CMC-4-3纖維素酶活力較CMC-4提高67.5%;其最適產(chǎn)酶條件是:37℃、pH 6.0、葡萄糖為碳源、蛋白胨為氮源、接種量2.0%、裝液量60 ml/250 ml。該菌株所產(chǎn)纖維素酶的最適反應(yīng)pH為6.0,且在4.0~7.0酶活力較穩(wěn)定;最適反應(yīng)溫度為50℃,在20~80℃范圍內(nèi)均保持穩(wěn)定;金屬離子Fe~(2+)、Mg~(2+)、Co~(2+)、K~+對(duì)酶有激活作用,其余離子均有不同程度抑制作用,而Cu~(2+)和Ca~(2+)抑制作用最強(qiáng),酶活力減弱近50%,是該酶的強(qiáng)效抑制因子。誘變前后菌株產(chǎn)酶條件和酶學(xué)性質(zhì)等部分表型發(fā)生了變化,而突變菌株顯示出了更寬泛的環(huán)境適應(yīng)范圍。據(jù)此,獲得一株高效產(chǎn)纖維素酶、耐受范圍廣的具纖維素降解能力的地衣芽孢桿菌,而CMC-4-3和CMC-4的表型可作為深入探討基因型變化的線索。
[Abstract]:A highly efficient cellulose degrading strain CMC-4, was obtained from straw returning soil. According to the morphology, physicochemical properties and 16s rDNA sequence analysis of the strain, it was identified as Bacillus licheniformis (Bacillus licheniformis). A stable and high yield cellulase mutant CMC-4-3. was obtained by sodium nitrite mutagenesis. The enzyme production conditions and enzymatic properties of CMC-4 and CMC-4-3 were compared and analyzed. The results showed that the cellulase activity of CMC-4 / CMC-4-3 was 67.5% higher than that of CMC-4, and the optimum conditions for enzyme production were as follows: pH 6.0 at 37 鈩，

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