白色瘤胃球菌对秸秆细胞壁和微晶纤维素的附着比较

Comparison of Adhesion Ability of Ruminococcus albus-7 to Corn Stalks Cell Wall and Crystalline Cellulose

本文采用比浊法测定了白色瘤胃球菌 (R .albus 7)对球磨、未球磨玉米秸秆细胞壁和微晶纤维素的附着率。结果表明 ,白色瘤胃球菌对球磨玉米秸细胞壁的附着能力与微晶纤维素相当 ,且二者显著高于未球磨玉米秸细胞壁的附着率 (P <0 .0 1) ,说明增加细胞壁颗粒表面积可以提高纤维分解菌的附着程度。白色瘤胃球菌经酶 (胰蛋白酶、蛋白酶 )和高碘酸钠修饰后 ,可显著降低其对玉米秸细胞壁和微晶纤维素的附着能力 (P <0 .0 1) ,而用甲醛或戊二醛固定细菌蛋白质对细菌的附着能力没有显著影响 ,推测细胞表面的蛋白质和碳水化合物同时参与了对植物细胞壁的附着。细菌经氯化锂修饰后附着能力下降最为明显 ,说明S层蛋白质 (单一蛋白质或糖蛋白 )

Adhesion ability of the cellulolytic bacterium Ruminococcus albus-7 to either ball milled corn stalks cell wall or not or crystalline cellulose was compared by incubating bacterial suspensions with these three substrates for 60 min at 39℃, allowing the substrates to precipitate for 60 min, centrifuging the mixtures at 1200 rpm for 5 min, and measuring the optical densities of the supernatants. There was no significant difference between the adhesion of R. albus-7 to ball milled corn stalks cell wall and to crystalline cellulose, but both of them were significantly higher than the grounded corn stalks cell wall (P<0.01). This result indicated that the increase of surface areas of substrates could enhance the extent of adhesion to substrates. The adhesion ability of R. albus-7 to ball milled corn stalks cell wall or crystalline cellulose was significantly decreased by the modifications with enzymes (trypsin or protease) or periodate (P<0.01), but the modifications with formalin and glutaraldehyde on adhesion of R. albus-7 to both of the substrates had no statistical difference compared with the control (P>0.05), which postulated that both the protein and carbohydrate existing on the bacterial cell surface involved the mechanism of adhesion. The adhesion ability of R. albus-7 was greatly decreased by the modification with LiCl, and this result strongly suggests that the S-layer protein may take an important role in the ad-(hesion) process of R. albus-7.