一株耐酸碱嗜热产甲烷菌的分离与系统发育分析

ISOLATION AND PHYLOGENETIC ANALYSIS OF THERMOPHLIC METHANOGEN WITH EXCELLENT CAPACITY OF ACID AND ALKALI-TOLERANT

从垃圾填埋场分离得到一株嗜热产甲烷菌RY3。该菌株具有优良的耐酸碱性能,其生长pH范围为5.5～10.5,最适生长pH为6.0～8.0。菌株RY3为革兰氏阳性,长杆状,多数单生,不运动;菌落浅黄色,形状近圆形;利用H_2+CO_2或甲酸盐作为唯一碳源生长,不利用乙酸盐,对氯霉素非常敏感。该菌最适生长温度为55～65℃,最适NaCl浓度为0～2%。根据形态和生理生化特性及16S rDNA序列分析将其初步定为Methanothermobacter thermautotrophicus。添加RY3菌液与仅添加厌氧污泥作为接种物相比一周内可使达到最大产甲烷速率所需时间缩短2/3,甲烷总产量提高约1.8倍。

A strain of thermophlic methanogen RY3 was isolated from Longquan refuse landfill of Chengdu. RY3 pos- sessed excellent acid and alkali-tolerant capacity. The pH-tolerant scale of RY3 was 5.5-10.5 and the optimum pH value for its growth was 6.0 -8.0. RY3 was G ＋ , long-red shape, monothetic and nonmotile, the colony was pale yellow with suborbicular-shape. Formate or H2 ＋ CO2 but not acetate was utilized by RY3 as sole C-source, and it was very sensitive to chloramphenicol. Besides, strain RY3 grew fastest at 55-65 ℃ and 0-2 % NaCl. Characteristics of modality and physi- ology with sequence analysis of the 16s rDNA gene of strain RY3 preliminarily showed that it was Methanothermobacter thermautotrophicus. The experiments indicated that the time which began to produce methane with the highest velocity could be shortened by 2/3 by adding RY3 in one week, and the total methane production also was 1.8 times than before.