一株玉米秸秆纤维素分解菌株的分离鉴定及酶学性质

Isolation, identification of a strain decomposing corn stalk and characterization of its cellulose

摘要:

【目的】筛选分离可以分解玉米秸秆纤维素的菌株。【方法】采用平板稀释法从土样中分离纯化得到能够分解玉米秸秆纤维素的菌株,对分离得到的菌株进行生理生化及分子鉴定,同时以菌株Penicillium spp. (CICC40361)作为对照,比较菌株纤维素酶和木质素酶的活性,研究不同因素对菌株纤维素酶活力的影响,确定菌株纤维素酶动力学常数Km 值。【结果】分离得到的菌株命名为PL2#,经生理生化及分子鉴定后,确定菌株PL2#为羊毛状青霉(Penicillium lanosum)。菌株PL2#的纤维素酶和木质素酶活力高于对照菌株Penicillium spp.;菌株PL2#的最优酶活测定条件为:1% CMC 底物浓度,pH 4.8,50 ℃,酶反应时间60 min 以及2 mL DNS添加量。【结论】羊毛状青霉(Penicillium lanosum)菌株PL2#比对照菌株Penicillium spp.具有更好地降解玉米秸秆纤维素的性能。

Abstract:

[Objective] The cellulose-decomposing strains for corn stalk were screened. [Methods] Agar dilution method was used to screen strains decomposing corn stalks from soil samples. Strains were identified by their morphological, physiological and biochemical properties and internal transcribed spacer sequence analysis. Then we compared the activities of cellulose and lignin degrading enzyme of the isolated strains with that of Penicillium spp. (CICC40361), studied the influence of different factors on cellulase activity, as well as the K_m values of the cellulase. [Results] A strain named PL2# was identified as Penicillium lanosum. The activities of cellulase and lignin enzyme of strain PL2# were higher than that of Penicillium spp. Conditions for optimal enzyme activity of strain PL2# was at 1% of carboxy methyl cellulose concentration, pH 4.8, 50 ℃, enzyme reaction time 60 min and 2 mL of DNS (3,5-dinitrosalicyclic acid) agent. [Conclusion] Strain PL2# (Penicillium lanosum) was better than the control strain Penicillium spp. in the degradation of corn straw cellulose.