Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Department of Environmental Biotechnology, KRIBB School of Biotechnology, Korea University of Science & Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea.
Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Department of Life Science, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
Bioresour Technol. 2019 Jun;281:56-65. doi: 10.1016/j.biortech.2019.02.062. Epub 2019 Feb 13.
This study examined the effects of a bacterial community and extracellular polymeric substances (EPS) on Ettlia sp. flocculation. The growth rate, flocculation efficiency (FE), bacterial community, and EPS profile of axenic and xenic Ettlia cultures were monitored during 46 days of cultivation. For the xenic culture, with a great abundance of growth-promoting and flocculation-inducing bacteria, the biomass density was 18.75% higher and its FE reached 100% in the mid-stationary phase. Moreover, microscopic observation and a quantitative analysis of the EPS revealed the exclusive presence of long filamentous EPS and more compact structure in the xenic Ettlia culture, possibly explaining its better FE. Notwithstanding, for the axenic culture, despite a lower biomass density and reduced abundance of EPS, its FE reached 92.54% in the mid-stationary phase. Thus, the role of the bacterial community was found to be supportive rather than vital for the high settleability of the self-flocculating Ettlia microalgal culture.
本研究考察了细菌群落和胞外聚合物（EPS）对 Ettlia 属絮凝聚的影响。在 46 天的培养过程中，监测了无菌和异养 Ettlia 培养物的生长速率、絮凝聚效率（FE）、细菌群落和 EPS 特征。对于异养培养物，由于存在大量促进生长和诱导絮凝的细菌，在中期，生物量密度高 18.75%，FE 达到 100%。此外，通过显微镜观察和 EPS 的定量分析发现，异养 Ettlia 培养物中存在独特的长丝状 EPS 和更紧凑的结构，这可能解释了其更好的 FE。尽管如此，对于无菌培养物，尽管生物量密度较低，EPS 丰度减少，但在中期 FE 仍达到 92.54%。因此，发现细菌群落的作用对于自絮凝 Ettlia 微藻培养物的高沉降性能是支持性的，而不是至关重要的。
