高效富集磷的周丛生物构建及其特征分析

Design of highly phosphorus-enriched periphytic biofilm and its characteristics

为强化周丛生物富集磷的性能,采用斜生栅藻与周丛生物共培养,形成新型的具有高效富集磷能力的人工周丛生物,并探究其特征与富集磷的机制。结果表明:与原周丛生物相比,人工周丛生物7 d磷富集量由(2.26±0.14)mg·g^(-1)显著提高到了(6.79±0.45)mg·g^(-1)。人工周丛生物有更为复杂的表面细胞结构以及更高的三维孔隙度,从而增加了表面磷的结合位点。人工周丛生物中光合作用相关生物,特别是绿藻的相对丰度提高了177.6%,从而增加了周丛生物胞内磷的吸附;胞外聚合物(EPS)中胞外蛋白质和多糖的含量增加,提升了周丛生物胞外磷的富集。周丛生物体系代谢产物的定量分析也表明:人工周丛生物中涉及到组氨酸和维生素B6代谢途径的8种关键代谢物质表达量上调。研究表明,斜生栅藻的引入改进了周丛生物的群落组成,尤其提高了光合自养微生物的丰度,促进了EPS的产率和关键代谢物质表达量的上调,最终提高了周丛生物的磷富集能力。

Periphytic biofilm is a micro-ecosystem that widely exists in natural surroundings and has the ability for phosphorus(P)entrapment and recovery.To further improve the efficiency of P entrapment by periphytic biofilms,a new type of artificial periphytic biofilm was designed by co-culturing Tetradesmus obliquus and original periphytic biofilm,and the characteristics and mechanism of P entrapment were also investigated.The results showed that compared with the original periphytic biofilm,the presence of Tetradesmus obliquus significantly increased the ability of P entrapment using artificial periphytic biofilm,and the P accumulation contents increased from(2.26±0.14)mg·g^(-1) to(6.79±0.45)mg·g^(-1) on the seventh day of the experiment.The artificial periphytic biofilm also had high compactness of the surface cells and porosity,which was beneficial to increase surface P binding sites and enhance P entrapment using artificial periphytic biofilms.Furthermore,the concentrations of intra-and extracellular P entrapped by the artificial periphytic biofilms were increased,partly due to the increase in the relative abundance of photosynthetic microorganisms and the content of extracellular polymeric substance(EPS).The relative abundance of Chlorophyceae and contents of extracellular protein and polysaccharide in the artificial periphytic biofilms increased by 177.6%,84.6%,and 23.7%,respectively.Moreover,the expression of eight key metabolites involved in histidine and vitamin B6 metabolic pathways were upregulated in artificial periphytic biofilms.The inclusion of Tetradesmus obliquus optimized the community composition of original periphytic biofilms;in particular,the relative abundance of photosynthetic microorganisms promoted the production of EPS and expression of key metabolites.As a result,the P entrapment capacity of the artificial periphytic biofilm was improved.In conclusion,an artificial periphytic with high efficiency in P enrichment was designed and constructed,which optimized the microbial community structure and function of the periphytic biofilm.This study provides a potential and promising approach for entrapping P from high-P-concentration water and wastewater.