Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
Center for Microbial Ecology and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium.
Bioresour Technol. 2022 Mar;348:126806. doi: 10.1016/j.biortech.2022.126806. Epub 2022 Feb 4.
Purple non-sulfur bacteria (PNSB) form an interesting group of microbes for resource recovery from wastewater. Solid/liquid separation is key for biomass and value-added products recovery, yet insights into PNSB aggregation are thus far limited. This study explored the effects of organic loading rate (OLR), hydraulic retention time (HRT) and water composition on the aggregation of Rhodobacter capsulatus in an anaerobic upflow photobioreactor. Between 2.0 and 14.6 gCOD/(L.d), the optimal OLR for aggregation was 6.1 gCOD/(L.d), resulting in a sedimentation flux of 5.9 kgTSS/(m.h). With HRT tested between 0.04 and 1.00 d, disaggregation occurred at the relatively long HRT (1 d), possibly due to accumulation of thus far unidentified heat-labile metabolites. Chemical oxygen demand (COD) to nitrogen ratios (6-35 gCOD/gN) and the nitrogen source (ammonium vs. glutamate) also impacted aggregation, highlighting the importance of the type of wastewater and its pre-treatment. These novel insights to improve purple biomass separation pave the way for cost-efficient PNSB applications.
紫色非硫细菌（PNSB）是从废水中回收资源的一类有趣的微生物。固液分离是回收生物质和增值产品的关键，但迄今为止，对 PNSB 聚集的了解有限。本研究探讨了有机负荷率（OLR）、水力停留时间（HRT）和水组成对 Rhodobacter capsulatus 在厌氧上流光生物反应器中聚集的影响。在 2.0 到 14.6 gCOD/（L.d）之间，最佳的聚集 OLR 为 6.1 gCOD/（L.d），导致沉降通量为 5.9 kgTSS/（m.h）。在 HRT 测试在 0.04 和 1.00 d 之间，在相对较长的 HRT（1 d）下发生了解聚，这可能是由于迄今为止未鉴定的热不稳定代谢物的积累。化学需氧量（COD）与氮比（6-35 gCOD/gN）和氮源（铵盐与谷氨酸盐）也影响聚集，突出了废水类型及其预处理的重要性。这些改善紫色生物质分离的新见解为高效、低成本的 PNSB 应用铺平了道路。
