论文部分内容阅读
拮抗链霉菌(Steptomyces spp.)R15菌株是从大白菜植株根际土壤分离得到的,其代谢产生的抗菌物质对多种植物病原真菌有很强的抑制作用。采用ABP选择性培养基诱导培养法,获得4株(R8,R15,R31和AS)产β-1,3-葡聚糖酶菌株。其中链霉菌R15菌株在ABP平板上培养7 d后,透明圈最大(>12 mm),澄清度最高。从R15菌株提取酶液,经10%￣75%的硫酸铵沉淀盐析、羟基磷灰石柱层析及DEAE-52柱层析得到纯化,纯化倍数为13.98,回收率达4.031%。经SDS-聚丙烯酰胺凝胶电泳测得该酶的分子量为41.3 kDa。酶特性研究结果表明,该酶作用的最适温度为55℃,最适pH为5.0,低于55℃、pH 7.5以下酶较稳定。Fe3+、K+、Cu2+、Hg2+对酶有抑制作用,而Ca2+、Fe2+、Ba2+、Mn2+、Al3+及Zn2+对酶有激活作用。
The strain R15 against Streptomyces spp. Was isolated from the rhizosphere soil of Chinese cabbage and the antibacterial substance produced by its metabolism has a strong inhibitory effect on many plant pathogenic fungi. Four strains (R8, R15, R31 and AS) producing β-1,3-glucanase were obtained by inducing culture with ABP selective medium. Streptomyces sp. Strain R15 cultured on ABP plate for 7 d, the largest transparent circle (> 12 mm), the highest clarity. The enzyme solution was extracted from the R15 strain and purified by 10% ~ 75% ammonium sulfate precipitation salting-out, hydroxyapatite column chromatography and DEAE-52 column chromatography. The purification rate was 13.98 and the recovery rate was 4.031%. The molecular weight of the enzyme was 41.3 kDa as determined by SDS-polyacrylamide gel electrophoresis. The results of enzyme characterization showed that the optimum temperature for the enzyme activity was 55 ℃, the optimum pH was 5.0, and the enzyme activity was stable at pH 7.5 when the temperature was below 55 ℃. Fe3 +, K +, Cu2 + and Hg2 + could inhibit the enzyme, while Ca2 +, Fe2 +, Ba2 +, Mn2 +, Al3 + and Zn2 + could activate the enzyme.