不同Cu离子浓度和pH值对云芝降解秸秆中木质素和纤维素的影响

Effects of Cu^(2+) and pH on Degradation of Lignin and Cellulose in Straw by Coriolus versicolor

云芝(Coriolus versicolor)对秸秆中木质素与纤维素的降解情况受不同Cu2+浓度和pH值条件的影响,设定不同条件可以提高木质素的降解率,降低纤维素的降解率,以更好地保存纤维素的完整性,实现秸秆中主要成分的分离。通过均匀设计法,设定不同的Cu2+浓度环境X1(0、1.0、2.0、4.0、6.0mmol/L)和不同pH值条件X2(2.2、2.8、3.4、4.0、4.6),测定相应条件下云芝的菌丝生长情况、木质素酶活力、纤维素酶活力以及秸秆中木质素和纤维素的降解率。结果表明:木质素的降解率与Cu2+浓度呈正相关,与pH值呈负相关;纤维素的降解率与pH值呈正相关,与Cu2+浓度呈负相关。通过试验所得方程预测得知,Cu2+浓度6mmol/L、pH2.2是优化的云芝降解、分离秸秆中主要成分的条件,在该条件下,由所得方程可知秸秆中木质素的降解率为16.1%,纤维素的降解率为27.7%。

Degradation of ligrtin and cellulose in straw by Coriolus versicolor can be affected by Cu^2＋ and pH. The optimal conditions for lignin and cellulose degradation were investigated through orthogonal array design. Activities of ligninase and cellulase, and degradation rates of llgnin and cellulose were used to evaluate the effects of Cu^2＋ and pH on degradation efficiency of Coriolus versicolor. Results indicated that the degradation rate of lignin was positively correlated to the concentration of Cu^2＋ and was negatively correlated to pH value; in contrast, the degradation rate of cellulose was positively correlated to pH value and was negatively correlated to Cu^2＋ concentration. The optimal conditions for Coriolus versicolor to decompose lignin and cellulose in straw were 2 mmol/L of Cu^2＋ and pH 2.2. The degradation rate of lignin exhibited 16.1% and the degradation rate of cellulose revealed 27.7% of reduction compared with natural degradation conditions.