Fe-Pd/MWCNTs提升己酸巨球菌产酸性能的影响机理  

Mechanism of the effect of Fe-Pd/MWCNTs on enhancing acid-producing properties of Megasphaera hexanoica

作　　者：王泽宇 范红叶 吕思妮 刘灵秀 陈浚 WANG Zeyu;FAN Hongye;LÜSini;LIU Lingxiu;CHEN Jun(Zhejiang Provincial Key Laboratory of Pollution Exposure and Health Intervention,Interdisciplinary Research Academy,Zhejiang Shuren University,Hangzhou 310015;College of Biology and Environmental Engineering,Zhejiang Shuren University,Hangzhou 310015;College of Environment,Zhejiang University of Technology,Hangzhou 310014;College of Geography and Environmental Science,Zhejiang Normal University,Jinhua 321004)

机构地区：[1]浙江树人学院交叉科学研究院,浙江省污染暴露与健康干预重点实验室,杭州310015 [2]浙江树人学院生物与环境工程学院,杭州310015 [3]浙江工业大学环境学院,杭州310014 [4]浙江师范大学地理与环境科学学院,金华321004

出　　处：《环境科学学报》2024年第1期333-340,共8页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.42207161,42177115);浙江省自然科学基金(No.LTGS23D030001);浙江省教育厅一般科研项目(No.Y202147579);浙江树人学院科研成果奖培育项目(No.2023XZ037)。

摘　　要：目前,纳米复合材料在促进生物降解和厌氧发酵方面引起了人们的极大关注.然而,有关Fe/Pd-MWCNTs对己酸菌的链延长过程的可行性和机制尚不清楚.因此,本研究考察了Fe/Pd-MWCNTs对Megasphaera hexanoica(己酸巨球菌)己酸产量的影响.结果表明,Fe-Pd/MWCNTs的添加可使最大己酸产量从1393 mg·L^(-1)增加至2562 mg·L^(-1),菌株最大生物量也从775.58 mg·L^(-1)提升至1145.82 mg·L^(-1).胞外聚合物(EPS)中与电子转移相关的蛋白质(PN)分泌量从67 mg·L^(-1)增加至88 mg·L^(-1),菌株产酸系统中的总电子当量从1589 mmol e-提升至1773 mmol e-,电子传输系统活性(ETSA)也从0.18 mg·g^(-1)·min^(-1)提升至0.39 mg·g^(-1)·min^(-1).电化学结果表明,EPS的电子转移能力从0.76μmol·g^(-1)提升至1.15μmol·g^(-1).基因结果显示,与乳酸氧化、己酸合成的关键功能基因的表达均不同程度得到了提升.机理分析表明,Fe/Pd-MWCNTs通过多种机制促进电子转移,包括刺激EPS分泌与上调碳延长途径中的关键代谢酶与合成酶的基因表达.本研究为纳米复合材料在厌氧发酵生物合成方面的利用提供了有效的策略.Nowadays,nanocomposites have attracted great interest in promoting biodegradation and anaerobic fermentation.However,the feasibility and mechanism of Fe/Pd-MWCNTs on the chain elongation process of Megasphaera hexanoica is not clear.Therefore,Fe-Pd/MWCNTs were used to examine the effect on the caproate production of Megasphaera hexanoic.The results showed that the addition of Fe-Pd/MWCNTs promoted an increase in the maximum caproate production from 1393 mg·L^(-1) to 2562 mg·L^(-1) and the maximum biomass of the strain from 2.983 mg·L^(-1) to 4.407 mg·L^(-1).Further,the amount of PN secretion associated with electron transfer in the EPS increased from 67 mg·L^(-1) to 88 mg·L^(-1) and the total electron equivalent in the acid-producing system of the strain increased from 1589 mmol e-to 1773 mmol e-,and the ETSA activity also increased from 0.18 mg·g^(-1)·min^(-1) to 0.39 mg·g^(-1)·min^(-1).Meanwhile,the electrochemical results showed that the electron transfer capacity of EPS increased from 0.76μmol·g^(-1) to 1.15μmol·g^(-1).Finally,the genetic results showed that the expression of key functional genes related to lactate oxidation and caproate synthesis were enhanced to different degrees.Mechanistic analysis indicated that Fe/Pd-MWCNTs promoted electron transfer through multiple mechanisms,including stimulation of EPS secretion and upregulation of gene expression of key metabolic and synthetic enzymes in the carbon elongation pathway.This study provides an effective strategy for the utilization of nanocomposites in anaerobic fermentation biosynthesis.

关 键 词：Fe-Pd/MWCNTs 碳延长 电子传递 己酸 胞外聚合物 

分 类 号：X172[环境科学与工程—环境科学]