木聚糖酶生产菌株的筛选及产酶条件的优化

以甘蔗渣半纤维素为碳源，从垃圾场土壤中分离到6株分解半纤维素的菌株。通过固态发酵的木聚糖酶活力比较筛选到1株木聚糖酶活力较高的菌株。该菌株18S rDNA序列与曲霉（Aspergillus sp.）的同源性达97%，根据对菌株形态学分析和18S rDNA序列分析的结果，将该菌株鉴定为曲霉HQ3。HQ3的最佳产酶条件为：甘蔗渣:麸皮为7:3（W/W），固液比为1:4（W/W），尿素0.4 %，pH7.0，温度30℃，发酵产酶时间4 d。在最佳产酶条件下，其木聚糖酶活最高可达3421U/g干曲。

Screening and condition optimization of a xylanase-producing strain

Six hemicellulose-decomposing strains were isolated from the refuse soil samples using bagasse hemicellulose as the sole carbon. The strain with high xylanase activity was screened and identified as Aspergillus sp. HQ3 by analysis of 18S rDNA sequences (97% similarity to Aspergillus sp.) and phenotypic properties. The optimum solid-state fermentation conditions for xylanase production were obtained as: bagasse: bran =7: 3 (W/W), solid: liquid =1: 4 (W/W), urea 0.4%, pH 7.0, fermentation temperature 30 ℃, fermentation time 4d. The activity of xylanase reached 3421 U/g koji under the optimum conditions.