1株光合细菌的分离鉴定、培养基优化及脱氮特性研究

Isolation and Identification of a Photosynthetic Bacterium Strain,Optimization of Culture Medium,and Study of Denitrification Characteristics

优化光合细菌发酵培养基,并研究其产酶特性和脱氮特性,以提升光合细菌在水质改良中的效果。采用双层平板法从河南省新乡市卫河水域底泥中分离筛选出1株光合细菌,命名为WH-1,通过菌株形态学观察及16S rDNA序列分析,确定分离菌株WH-1为沼泽红假单胞菌(Rhodopseudomonas palustris)。为提高培养的WH-1菌液浓度,采用单因素和正交试验优化发酵培养基,得到最佳培养基配方:CH_(3)COONa 1.0 g/L、NH4Cl 0.5 g/L、酵母浸粉3.0 g/L、NaCl 2.0 g/L、K_(2)HPO_(4)0.2 g/L、NaHCO_(3)3.0 g/L、MgSO_(4)0.2 g/L。培养基优化之后,经流式细胞仪计数,WH-1菌液浓度达到4.37×10^(9)个/mL,较优化前增长43.33%。产酶特性试验结果显示,菌株WH-1可以产纤维素酶、淀粉酶,但不能产蛋白酶。在高质量浓度的氨氮(NH_(3)-N)、亚硝酸氮(NO_(2)^(-)-N)环境中,WH-1菌株的NH_(3)-N、NO_(2)^(-)-N降解率分别达到49.89%和31.15%。综上,成功分离出1株性能优良的光合细菌WH-1,优化了培养基组成,该菌株展现出良好的产酶性能和脱氮能力。

In order to enhance the effects of photosynthetic bacteria in water quality improvement,the fermentation medium of photosynthetic bacteria was optimized and the enzyme production and denitrification characteristics were studied.A strain of photosynthetic bacterium named WH-1 was isolated and screened from the sediment of Weihe River in Xinxiang City,Henan Province by the double-layer plate method.Through morphological observation and 16S r DNA sequence analysis,the isolated strain WH-1 was identified as Rhodopseudomonas palustris.To increase the concentration of WH-1 in liquid medium,single factor and orthogonal experiments were utilized to optimize the fermentation medium.The optimal medium formula was obtained:CH_(3COONa) 1.0 g/L,NH4Cl 0.5 g/L,yeast extract 3.0 g/L,NaCl 2.0 g/L,K_(2)HPO_(4)0.2 g/L,NaHCO_(3)3.0 g/L,MgSO_(4)0.2 g/L.After the optimization of the medium,the concentration of WH-1 reached 4.37×10^(9)cells/mL,which increased by 43.33%compared with that before optimization.The results of the enzyme production characteristic test showed that the strain WH-1 could produce cellulase and amylase,but could not produce protease.In the environment with high concentration of ammonia nitrogen(NH_(3)-N)and nitrite nitrogen(NO_(2)^(-)-N),the degradation rates of NH_(3)-N and NO_(2)^(-)-N o WH-1 strain reached 49.89%and 31.15%,respectively.In conclusion,a strain of photosynthetic bacterium WH-1 with excellent performance is successfully isolated,and the composition of the medium is optimized.WH-1 shows good enzyme production and denitrification ability.