纤维素降解真菌分离筛选、产酶特性及高效水解菌系的初步构建

Isolation of Cellulose-Degradation Fungi,Their Zymogenic Characteristics, and Preliminary Design of High Effect Complex Microbial Communities

用稀释法和表面消毒法分别从腐烂木屑和霉变树枝中分离纤维素降解真菌,获得两个菌株,编号为34和H。在以木屑为唯一营养的培养基上,两个菌株生长良好;在羧甲基纤维素钠（CMC-Na）培养基上,真菌H生长速度明显大于真菌34,但所形成的刚果红透明圈直径则真菌34明显大于H。研究两个菌株的生物学及产酶特性发现：复杂多糖比简单双糖或单糖更利于菌株的生长,淀粉是它们的最佳碳源;当MS为无机盐、滤纸或CMC-Na为碳源、pH为6.0-7.0时,两个菌株的纤维素酶活较高;其中,真菌34的最高FPase和CMCase为144.14和325.67 U/L,真菌H则为111.38和328.47U/L。真菌34与四株弱纤维素降解细菌共培养构建成四组高效纤维素水解菌系,可将滤纸纤维完全降解为水溶性化合物。对真菌34进行形态学与分子生物学鉴定,该菌为B.dothidea的近缘种。

Two fungi strains marked as 34 and H were isolated from rot wooden mud and mildewing branch by employing the methods of serial dilution and surface sterilization ,respectively. The two strains grew well on the wooden scraps. The strain H grew faster but with smaller Congo red transparent rings than the strain 34 on the media appending carboxymethylcellulose sodium （CMC-Na）. Studies on the biological and zymogenic characteristics of the two fungi showed that polysaccharides were more favorable than disaccharides and monosaccharides, and starch was the best carbon source for the growth of both strains. The highest FPase and CMCase activity of the two stains appeared when they grew in the media with MS as inorganic salts, filter-paper or CMC-Na as carbon source, and pH 6.0 -7.0. The highest value of FPase and CMCase activity of the stain 34 were 144.14 and 325.67 U/L, respectively, and which of the stain H were 111.38 and 328.47 U/L, respectively. Stain 34 with cellulose-degradation bacteria were designed four groups of microbial communities which could hydrolyze the filter paper completely. The morphological and molecular identification indicated that the stain 34 was the species closely related to B. dothidea.