酸性半纤维素降解细菌的筛选与鉴定

从南方酸性水稻土和腐烂秸秆中采集样品,经初筛、复筛获得4株产生明显水解圈且D/d值较大同时传代效果稳定的酸性半纤维素降解细菌。DNS法测定4株细菌半纤维素酶活力,最终结合其产酶速度及酶活大小得到菌株NB8,液体摇瓶发酵72 h其半纤维素酶活达85.12 U/mL。经形态学观察和生理生化指标测定,初步确定该菌为芽胞杆菌属。结合16S rDNA基因序列分析结果,可以初步鉴定NB8为短小芽胞杆菌(Ba-cillus pumilus)。

Screening and Characterization of Acidic Hemicellulose-Degrading Bacteria

Four acidic hemicellulose-degrading bacteria strains were isolated from acid paddy soil and decomposed straw samples collected in South China after primary and repeatedly screening with significant hydrolyzing ring and fairly large D/d value and stable generation passing effect.Their hemicellulose-degrading activity was determined with DNS method,and obtained strain NB8 with final combining both the production speed and the scale of hemicellulase activity.The hemicellulase activity was at 85.12 U/mL after 72 hours＇ liquid fermentation in shaker flask.This strain was initially classified as the genus of Bacillus on the basis of its morphological,physiological and biochemical properties.Combined with the result of 16S rDNA gene analysis,strain NB8 was initially identified as Bacillus pumilus.