β-葡萄糖苷酶的发酵工艺优化及在木糖渣酶水解中的应用

Optimization of β-D-glucosidase fermentation condition and its application in corncob residues hydrolysis

木糖渣有较高的纤维素含量,可以用作诱导产生β-葡萄糖苷酶的碳源。本文以木糖渣为诱导碳源,优化了黑曲霉发酵产β-葡萄糖苷酶的工艺。首先利用Plackett-Burman实验设计在6个因素中筛选出了影响产酶的主要因素,分别为麦麸、硫酸铵、硝酸钠。在筛选基础上,利用三因素五水平的中心组合对3个因素进行了进一步的优化,并用响应优化器得到了产酶的最佳条件麦麸、硫酸铵、硝酸钠的浓度分别为26.7g/L、10.0g/L、10.0g/L,在得到的最佳条件下,酶活可以达到15.0IU/mL。对拟合模型进行了方差分析,结果表明模型的R2值为92.12%,P值为0,模型拟合较好,可以对实验结果进行预测。以木糖渣为底物,用诱导制备的复配酶液验证了其水解效率,结果表明当里氏木霉粗酶液与黑曲霉粗酶液1︰1复配时,酶水解效率为里氏木霉粗酶液的4倍。

Corncob residues are one kind of lignocellulosic material which having abundant of cellulose content and can be used as inducing carbon source to produce cellulose degradation enzyme.This article reported optimization process using Aspergillus niger to produceβ-D-glucosidase.Firstly,a Plackett-Burman design was used to select the main factors which had obvious significance on the production ofβ-D-glucosidase from six factors.The results suggested that wheat bran,ammonium sulfate and sodium nitrate had significant effect on the production ofβ-D-glucosidase.On the basis of selection,a central composite design(CCD)was employed to optimize the process.It was suggested that the most optimization concentration of wheat bran,ammonium sulfate and sodium nitrate was 26.7g/L,10.0g/L and 10.0g/L,respectively.Under the optimization condition theβ-D-glucosidase activity was at 15.0IU/mL.Analysis of variance(ANOVA)was used for graphical analyses of the data to obtain the interaction between the process variables and the responses.The R2 coefficient 92.12%and the p value 0 indicated a satisfactory adjustment of the quadratic model to the experimental data.The crude enzyme which prepared under the optimization condition was used to hydrolyze Corncob residues.The results suggested that when the crude enzyme prepared by Trichoderma reesei B4 and Aspergillus niger JH-1 were blended at the ratio of 1︰1 enzymatic hydrolysis efficiency of the mixed crude enzyme was 4 times of the crude enzyme prepared by Trichoderma reesei B4.