产甘露聚糖酶菌株的筛选·鉴定及酶活性的初步研究

Preliminary Study on Selection and Identification of a Mannanase-producing Strain and Its Enzymatic Properties

[目的]从土壤中分离得到产甘露聚糖酶的菌株。[方法]以魔芋粉为底物,从崐嵛山采集的土壤中,经平板法筛选得到产甘露聚糖酶的优势菌株。将该菌株的一段16S rDNA片段进行序列分析以确定其所属菌种,并对该菌株的发酵条件和酶的性质做初步研究。[结果]该菌株在不同的培养基中产酶量不同,不同温度下的相同培养基中产酶量也不同,在LB培养基中,27℃下培养较30℃利于该菌株产酶,而SOC培养基在30℃下培养较27℃利于该菌株产酶;该菌株所产酶的最适反应pH为7.0,最适反应温度为55℃,之后温度升高酶活力会急剧下降。在最适反应条件下测得酶活力可达95.3 U。[结论]为甘露聚糖降解产物的工业化应用提供了参考。

[ Objective ] This study aimed to identify a mannanase-producing strain isolated from soil. [ Method ] With konjac powder as the substrate, a mannanase-producing dominant strain was isolated from the soil samples collected from Kunyu Mountain by using plate selection method. Sequence analysis of the 16S rDNA fragment of the strain was conducted, and the strain was identified as Bacillus subtilis. Fermenta- tion conditions and enzymatic characteristics were studied preliminarily. [ Result] Experimental result showed that enzyme yield of this strain was different in different medium and in the same medium at different temperature. Enzyme yield of this strain in LB medium was higher when incubated at 27 ℃ than at 30 ℃ however, incubation at 30 ℃ was more conducive to the enzyme production than incubation at 27 ℃ in SOC medium. The optimal reaction pH was 7.0 and the optimal reaction temperature was 55 ℃ for enzyme production of this strain. When the tem- perature was above 55 ℃, enzyme activity declined sharply with the raise of temperature. ; Under the optimum conditions, enzyme activity could achieve 95.3 U. [ Conclusion] This study provided a reference for the industrial application of degradation products of mannan.