混合培养对城市污水厂二级出水培养能源微藻的生长促进作用

Effects on the growth characteristic by mixed culture of three energy microalgae species using domestic secondary effluent

利用城市污水培养能源微藻可以实现水质净化和生物质生产的耦合,备受关注。生物质生产效率较低是限制其大规模应用的主要因素之一,混合培养是提高微藻生物质产率的一种潜在方法。为筛选出城市二级出水条件下合适的能源微藻混合藻种,考察了二级出水条件下3株高含油脂藻种栅藻LX1(Scenedesmus sp.LX1)、椭圆小球藻YJ1(Chlorella ellipsoidea YJ1)和雨生红球藻(Haematococcus pluvislis)单一藻种和两两混合培养时的生长特性,比较了各微藻单一藻种及两两混合培养时的生长特性参数及生物质产量。研究结果表明,3种微藻的两两混合组合均能在二级出水条件下正常生长,各微藻干物质量浓度在第10天左右均能达到100 mg·L-1左右。与栅藻LX1和椭圆小球藻YJ1相比,雨生红球藻在两两混合培养条件下表现出更高的藻细胞干物质量浓度增长趋势。3种微藻的内禀生长速率均显著高于各自的单一培养,栅藻LX1和雨生红球藻混合培养时分别达到最高内禀增长速率(分别为1.36 d-1、0.97 d-1)。栅藻LX1与雨生红球藻混合培养时比生长速率分别为0.59d-1和0.42 d-1,分别比栅藻LX1和雨生红球藻的单一藻种培养提高了36%、9.0%。与单一藻种相比,混合培养促进了微藻的生物质产量,栅藻LX1和雨生红球藻混合藻种的生物质产量(277 mg·L-1)分别比栅藻LX1、雨生红球藻的单一藻种培养提高了64%和42%。栅藻LX1与雨生红球藻藻种组合具备作为二级出水条件下能源微藻培养合适混合藻种的潜力。

Energy microalgae cultivation in wastewater system is very promising for the combination of water purification and energy production. The coupled technology is limited by low biomass productivity of microalgae in wastewater. Mixed culture of specific energy microalgae is a potential solution to address the problem. In order to find out the proper mixed microalgae strains, Scenedesmussp. LX1,Chlorella ellipsoidea YJ1 andHaematococcus pluvisliswere chosen to study the growth characteristic among different microalgal species combinations under secondary effluent of domestic wastewater. Comparisons of the growth characteristic and biomass productivity were conducted among different microalgal species combinations. The results indicated that different microalgal species combination ofScenedesmus sp. LX1,Chlorella ellipsoideaYJ1 and Haematococcus pluvialis can grow well, with biomass of every microalgae growing up to 100 mg·L-1 on day 10. Compared withScenedesmus sp. LX1 andChlorella ellipsoidea YJ1,Haematococcus pluvislis exhibited higher biomass growth potential. The intrinsic growth rate of the three microalgae in the mixed culture was higher than the mono-culture of them. The highest intrinsic growth rate ofScenedesmus sp. LX1 andHaematococcus pluvislis （1.36 d-1, 0.97 d-1, respectively） was obtained under the mixed culture of them.Scenedesmussp. LX1 andHaematococcus pluvislisin the mixed culture of them behaved higher specific growth rate （0.59 d-1, 0.42 d-1, respectively） than each mono-culture of them. Compared with the mono-culture of Scenedesmus sp. LX1,Chlorella ellipsoideaYJ1 and Haematococcus pluvialis, the biomass productivity was enhanced in the mixed cultures. The biomass productivity in the mixed culture ofScenedesmus sp. LX1 andHaematococcus pluvialis was increased by 64% and 42% than the monoculture ofScenedesmus sp. LX1 andHaematococcus pluvialis, respectively. The mixed culture ofScenedesmus sp. LX1 andHaematococcus pluvialis are potential strains used in energy microalgae cultivation in secondary effluent of domestic wastewater.