冬季自然温度下外加AHLs对ANAMMOX生物膜的影响

Effect of exogenous AHLs on ANAMMOX biofilm process under natural temperature in winter

低温条件下维持厌氧氨氧化(ANAMMOX)生物膜的高效性能是一个巨大的挑战,研究考察了在冬季自然温度下两种外源信号分子己酰基高丝氨酸内酯(C6-HSL)和辛酰基高丝氨酸内酯(C8-HSL)对ANAMMOX生物膜工艺的影响.结果表明,添加C6-HSL和C8-HSL促进了低温波动下工艺的脱氮性能,分别使总氮去除率提高了48.09%和44.36%,同时有效增强了ANAMMOX生物膜低温环境的适应性.低温波动下,C6-HSL和C8-HSL调节了肼脱氢酶(HDH)的活性(分别是对照组的1.77和1.57倍),显著提高了ANAMMOX活性;促进了胞外聚合物(EPS)特别是TB-EPS中PN和PS的分泌,并改变蛋白质二级结构的疏水性,从而增强生物膜附着性能(OD600值分别提升55.12%和68.32%).此外,基于16S rRNA测序发现,C6-HSL和C8-HSL有效促进了低温下Candidatus Kuenenia的生长,使氮代谢相关功能基因丰度上调.

Maintaining the efficient performance of anaerobic ammonia oxidation(ANAMMOX)biofilm under low-temperature conditions is a great challenge.The effects of two exogenous signaling molecules,hexanoyl homoserine lactone(C6-HSL)and octanoyl homoserine lactone(C8-HSL),on the ANAMMOX biofilm process were examined under the natural temperature in winter.The results showed that the addition of C6-HSL and C8-HSL promoted the nitrogen removal performance of the process under low temperature fluctuation,which increased the total nitrogen removal by 48.09%and 44.36%,respectively,and effectively enhanced the adaptability of ANAMMOX biofilm to the low-temperature environment.Under the low-temperature fluctuation,C6-HSL and C8-HSL regulated the activities of hydrazine dehydrogenase(HDH)(1.77and 1.57times higher than that of the control group,respectively),which significantly enhanced the activities of ANAMMOX;promoted the secretion of PN and PS in the extracellular polymers(EPS),especially in the TB-EPS,and altered the hydrophobicity of the secondary structure of proteins,which led to enhanced biofilm adhesion performance(The OD600values were enhanced by 55.12%and 68.32%,respectively).In addition,based on 16S rRNA sequencing,C6-HSL and C8-HSL effectively promoted the growth of Candidatus Kuenenia at low temperature and up-regulated the abundance of functional genes related to nitrogen metabolism.