沉积物异化铁还原耦合植酸去磷酸化

Phytic Acid Dephosphorylation Coupled with Dissimilatory Iron Reduction in Sediment

研究沉积物中微生物驱动的异化铁还原与有机磷降解转化的耦合作用,对深入阐明水体富营养化发生机制、控制环境磷污染和应对潜在的全球性磷危机具有重要的现实意义。该研究以沉积物异化铁还原与有机磷降解转化耦合的环境效应为切入点,探究了异化铁还原促进植酸有机磷去磷酸化的可行性。首先通过对武汉东湖自然沉积物中有机磷与亚铁含量的监测,以及两者之间的相关性分析,发现在以有机质降解为驱动力的早期成岩过程中,三价铁逐渐被还原为亚铁,同时伴随着有机磷含量的降低,揭示沉积物中铁的异化还原可能促进有机磷的降解转化;接着利用富集的沉积物内源微生物群落在实验室构建“异化铁还原微生物群落+水铁矿+植酸”微宇宙模拟系统,开展了铁还原微生物群落驱动异化铁还原对植酸有机磷降解转化作用的研究,进一步证实铁的异化还原能促进植酸有机磷的去磷酸化并生成PO_(4)^(3-),很可能是诱导水体富营养化的潜在新机制。

To study the coupling effect between dissimilatory iron reduction(DIR)and organic phosphorus(OP)transforma⁃tion in sediments is of practical importance to further illuminate the mechanism for water eutrophication,control environmen⁃tal phosphorus pollution,and cope with the potential global phosphorus crisis.This study took the coupled environment effect between DIR and OP transformation in sediments as point of penetration and explored the feasibility of DIR in promoting the dephosphorylation of phytic acid.Firstly,the concentration of OP and Fe(Ⅱ)in the natural sediment of East Lake in Wuhan was monitored.The correlation analysis between their concentration indicated that Fe(Ⅲ)was gradually reduced to Fe(Ⅱ),accompany⁃ing with a decrease in OP concentration,in the early diagenetic process driven by organic matter degradation.This could dem⁃onstrate dissimilatory iron reduction might promote OP transformation in sediment.Then,the simulation microcosm system“dissimilatory iron reducing microflora(DIRM)+ferrihydrite+phytic acid(PA)”was established using the enriched DIRM from sediment,to study the degradation and transformation of phytic acid OP by dissimilatory iron reduction mediated by DIRM.The findings further confirmed that DIR could significantly facilitate PA dephosphorylation to produce PO_(4)^(3-),which would be a potential new mechanism for inducing water eutrophication.