棉花秸秆纤维素降解菌的筛选鉴定 与降解棉秆效果研究

【目的】 利用微生物学和分子生物学手段筛选和鉴定棉秆表面附着的真菌,获得具有高效纤维素分解能力的真菌。【方法】 通过将棉花秸秆接种至不同选择性培养基中,分离挑选水解圈较大的菌株,进行镜检和分子生物学鉴定;并同时对菌株进行滤纸酶活性(FPA)和羧甲基纤维素钠(CMC-Na)糖化活力的测定,以及连续(25 d)观测棉秆纤维的失重率。【结果】 主要4株菌种水解圈直径大小排序为,SN-1＞SN-4＞SN-3＞SN-4(P=0.013)。对于CMC-Na糖化活力,24~96 h时SN-1菌种显著低于其它3个菌种(P＜0.05),120 h时,各菌种处理间差异不显著(P＞0.05)。对于FPA活性,第24和120 h时,SN-1和SN-4菌种显著高于SN-2和SN-3菌种(P＜0.05);其它时间点,各菌种按活性高低排序为:SN-1、SN-4＞SN-3＞SN-2(P＜0.05)。通过镜检和分子生物学鉴定,得到4株菌种分别为:SN-1为黑曲霉(Aspergillus niger),SN-2为赤霉(Gibberella moniliformis),SN-3为链格孢霉(Alternaria nees),SN-4为青霉菌(Penicillium italicum)。【结论】 黑曲霉降解棉花秸秆的效果最为显著。对于CMC-Na糖化酶活力、滤纸酶活性以及棉花秸秆的实际失重率(降解率),接种黑曲霉或青霉菌时表现均最佳。

Screening and Identification of Cellulolytic Strains from Cotton Straw and Its Effect on Degradation of Cotton Stalk

【Objective】 This study aims to screen and identify fungi which adhere on the surface of the cotton by using microbiology and molecular biology methods in order to obtain fungi with high cellulose decomposition ability.【Method】 The cotton straw was inoculated into different selective media, and the larger hydrolysis circle of strains was separated and selected. At the same time the strains' filter paper enzyme activity (FPA) and sodium carboxymethyl cellulose (CMC-Na) saccharification vitality were determined, and besides, the weight loss rate of cotton stalk fiber was observed continuously for 25 days.【Result】 The diameter of the hydrolysis ring of the 4 main strains was SN-1 > SN-4 > SN-3 > SN-4 (P =0.013). In terms of CMC - Na saccharification vitality, SN - 1 was significantly lower than other three strains (P < 0.05) at 24-96 h, and there was no significant difference between different strains of treatments (P > 0.05) at 120 h. In terms of FPA activity, SN and SN 1-4 strains was significantly higher than SN - 2 and SN - 3 strains (P < 0.05) at 24 and 120 h, at other time points, the strains were sorted according to the activity level: SN-1, SN-4 > SN-3 > SN-2 (P < 0.05). There were 4 bacterial strains obtained by using the method of microscopic and molecular identification, SN - 1 was Aspergillus nige r, SN - 2 was Gibberella moniliformis , SN - 3 was Alternaria nees and SN - 4 was Penicillium italicum . 【Conclusion】 The effect of Aspergillus niger on the degradation of cotton straw was the most remarkable. The activity of CMC-Na saccharifying enzyme, the activity of filter paper enzyme and the actual weight loss rate (degradation rate) of cotton straw were the best when inoculated with Aspergillus niger or Penicillium italicum .