高温油藏生物膜内硫酸盐还原菌的腐蚀机理及防治策略

硫酸盐还原菌(sulfate-reducing bacteria,SRB)广泛分布于高温、高压及高盐的石油油藏中,在油藏硫循环中起主导作用。SRB能在油藏生物膜内生长,有微量低分子有机酸时利用硫酸盐为电子受体并将其还原成硫化氢。硫化氢会腐蚀管道,导致原油泄露等其他安全问题,每年造成的经济损失超过7 000亿元。本文首先总结了油藏生物膜内微生物菌群多样性,分析了生物膜内SRB及其相关菌群的协同腐蚀机理;然后讨论了高温油藏SRB介导的硫氮氢生物地球化学循环过程、胞外电子传递机制及其腐蚀作用,并通过几个高温油藏SRB生物膜内腐蚀的现场案例进一步阐明了SRB的腐蚀机制。在此基础上,提出了应对高温油藏生物膜内SRB腐蚀的生物纳米防治策略,这为高温油藏管道防腐提供了新思路。     

参与金属腐蚀的微生物及其控制

参与金属腐蚀的微生物及其控制王公德（山东省潍坊市第一职业中专２６１０２１）微生物对金属的腐蚀,早在本世纪初就已被人们所发现。到了３０年代,荷兰学者克尔提出硫酸盐还原菌参与金属腐蚀中阴极去极化理论后才开始受到重视。每年因微生物腐蚀造成的损失,占金属腐蚀...     

海洋环境下腐蚀微生物研究进展北大核心

海洋环境的复杂多变性使海洋腐蚀成为一个日益严重的全球性问题。海洋腐蚀在造成巨大经济损失的同时,还带来了严重的环境污染以及人员安全问题,使其成为海洋经济发展中必须要解决的关键问题。据统计海洋环境中20%的腐蚀由微生物引起,腐蚀微生物(microbiologically influenced corrosion,MIC)以生物膜的形式存在于金属表面,其主要包括细菌、古菌、真菌及藻类等。基于对以往研究的综述,本文总结了这4类海洋微生物的研究进展,阐述了海洋腐蚀环境中腐蚀微生物的种类、群落组成影响因素及其作用机理等内容;同时,文中概述了微生物对金属材料促进腐蚀或抑制腐蚀的影响因素及其作用机制,并归纳了当前海洋环境中微生物腐蚀的防治方法;最后,本研究对海洋环境下微生物腐蚀研究及防治的发展趋势进行了论述,以期为腐蚀机制的研究与防腐工作的实施提供参考。     

硫酸盐还原菌与油田金属管道腐蚀

硫酸盐还原菌（sulfate-reducing bacteria,SRB）是一类利用硫酸盐和其他氧化态硫化物,或利用元素硫作为电子受体,并将其还原成S2-的原核生物。在长时间开采原油过程中,地层需要通过金属管道注水来维持油气输出压力,而输水管壁上很容易形成生物膜垢。该生物膜垢的形成是微生物腐蚀发生的必要条件,也是微生物对金属腐蚀问题难以解决的主要原因。     

人工纳米材料与生物膜相互作用机制及影响因素研究进展

人工纳米材料在水体中的环境行为与生物环境安全问题成为环境科学领域研究的热点,人工纳米材料与生物膜相互作用机制和影响因素是其中迫切需要研究解决的关键科学问题。本文主要探讨了人工纳米材料释放进入到水体中后对生物膜细菌活性、微生物群落结构、净污活性等的毒性效应,分析了人工纳米材料对生物膜的毒性作用机制及其影响因素,同时探讨了生物膜对人工纳米材料的吸附作用及机理,为深入研究人工纳米材料与生物膜的相互作用机制提供了重要的理论基础。     

细菌群体感应对细菌生物膜形成与调控的研究进展

细菌群体感应(quorum sensing,QS)是细菌细胞之间通过感受自诱导物来调控细菌群体行为的现象。细菌生物膜(bacterial biofilm,BBF)是细菌在生长过程中为适应生存环境而吸附于惰性或活性材料表面形成的一种与浮游细胞相应的生物被膜,其结构包括细菌和自身分泌的细胞外基质(extracelluar polymeric substance,EPS)。生物膜可以保护细菌免于外界恶劣环境的影响,增加其抗药性,为细菌生长提供天然的有利屏障。细菌群体感应是细菌调控生物膜形成的重要机制之一,本文中,笔者综述了细菌群体感应在生物膜生成过程中的调控作用,分析了细菌生物膜抑制与降解策略,旨在为医药与食品工业中降低细菌耐药性和细菌抗性提供理论依据。     

乳酸菌群体感应与其肠道生物膜形成的研究进展

肠道内栖息着数量庞大且复杂的微生物菌群,是一个具有生物多样性的微环境,菌群在调节宿主肠道健康中发挥着重要作用。群体感应(quorumsensing,QS)是细菌间通过化学信号分子进行信息传递的重要方式。本文综述了QS系统组成、信号转导机制及AI-2/LuxS系统对肠道生物膜形成的调控,介绍了乳酸菌AI-2/LuxSQS系统及其在调控生物膜形成上的作用。通过肠道乳酸菌QS与生物膜形成综述分析,旨在为肠道屏障功能和健康调控提供新思路。     

生物膜中不同种属微生物的交流与合作

自然界中的微生物可附着于载体表面形成高度组织化、系统化的微菌落膜性聚合物, 即生物膜. 与浮游状态的微生物不同, 生物膜中不同种属微生物进行着复杂的交流与合作, 产生“1+1>2”的非线性相互作用, 从而使生物膜在整体上表现出一系列新的生物学特征. 生物膜给人们的生活生产带来很多不利的影响, 如引起顽固性感染性疾病威胁人类健康、破坏输水管道系统导致工业损失等; 但另一方面, 生物膜也可发挥积极作用, 如降解污染物修复环境, 形成生物屏障保护生态等. 如何认识生物膜、如何趋利避害使生物膜造福于人类已成为当今世界多领域关注和研究的重要课题. 从生物膜的形成、代谢产物与信号分子、水平基因转移及其与外界环境的关系等方面对生物膜中交流与合作的研究进展及意义进行了综述, 并提出应从“微生物组学”的高度整体认识生物膜.     

细菌生物膜群体感应系统研究进展

细菌生物膜群体感应系统是指细菌通过分泌信号分子并通过感知其在周围环境中的浓度,调控某些基因的特异性表达及生理功能和生活习性的系统,是细菌生命活动的主要调控机制之一。通过对细菌生物膜群体感应的研究,可以了解其内部机理和特性,从而找到抑制生物膜有害作用的最好方法。对细菌生物膜群体感应系统的种类、特征和相关应用的研究进行综述。     

废水处理中群体感应调控行为研究进展

群体感应是微生物在繁殖过程中分泌一些特定的信号分子,当信号分子浓度达到一定阈值后,可以调控某些基因表达,从而实现信息交流的现象.群体感应调控着生物膜形成、公共物质合成、基因水平转移等一系列社会性行为,广泛存在于各类微生物信息交流中.活性污泥、生物膜和颗粒污泥等生物聚集体广泛存在群体感应现象,了解和认识群体感应与微生物之间的调控行为,对于废水处理具有重要意义.本文综述了感应信号分子的分类、群体感应调控机制,群体感应在活性污泥、生物膜、好氧颗粒污泥和厌氧颗粒污泥等废水处理中的调控行为的研究进展,并对废水处理中群体感应的研究进行了展望,以期为深入理解废水处理中群体感应调控行为提供参考.     

Understanding microbial inhibition of corrosion. A comprehensive overview

Microorganisms are able to drastically change the electrochemical conditions at the metal/solution interface by biofilm formation. These changes can range from the induction or acceleration of corrosion to corrosion inhibition. Any inhibitory action developed by bacteria may be accomplished within the varied and complex biofilm/corrosion products interactions occurring on a biofouled metal surface.Biocorrosion and its counter process, microbial inhibition of corrosion, are rarely linked to a single mechanism or to a single species of microorganisms. Microorganisms can induce corrosion inhibition according to two general mechanisms or their combination: i) neutralizing the action of corrosive substances present in the environment; ii) forming protective films or stabilizing pre-existing protective films on a metal. Different practical cases illustrating these mechanisms are presented in this overview.It must be stressed that some times the inhibitory action of bacteria can be reversed to a corrosive action in bacterial consortia located within biofilm thickness.     

The effect of mucin,fibrinogen and IgG on the corrosion behaviour of Ni–Ti alloy and stainless steel

In this study, Ni–Ti alloy and stainless steal were exposed to artificial saliva containing fibrinogen, IgG or mucin, and the resultant corrosion behavior was studied. The purpose was to determine the mechanisms by which different types of protein contribute to corrosion. The effect of different proteins on the electrochemical resistance of Ni–Ti and SS was tested by potentiodynamic polarization, and the repair capacity of passivation film was tested by cyclic polarization measurements. The dissolved corrosion products were determined by ICP-OES, and the surface was analyzed by SEM and AFM. The results showed fibrinogen, IgG or mucin could have different influences on the susceptibility to corrosion of the same alloy. Adding protein lead to the decrease of corrosion resistance of SS, whereas protein could slow down the corrosion process of Ni–Ti. For Ni–Ti, adding mucin could enhance the corrosion stability and repair capacity of passivation film. The susceptibility to pitting corrosion of Ni–Ti and stainless steal in fibrinogen AS is not as high as mucin and IgG AS. There are different patterns of deposition formation on the metal surface by different types of protein, which is associated with their effects on the corrosion process of the alloys.     

Influence of EPS isolated from thermophilic sulphate-reducing bacteria on carbon steel corrosion

Extracellular polymeric substances (EPS) were isolated by centrifugation of thermophilic sulphate-reducing bacteria (SRB) grown in API-RP38 culture medium. The protein and polysaccharide fractions were quantified and the highest concentrations were extracted from a 14-day old culture. The effect of EPS on carbon steel corrosion was investigated by electrochemical techniques. At 30°C, a small amount of EPS in 3% NaCl solution inhibited corrosion, whilst excessive amounts of EPS facilitated corrosion. In addition, the inhibition efficiency of EPS decreased with temperature due to thermal desorption of the EPS. The results suggest that adsorbed EPS layers could be beneficial to anti-corrosion by hindering the reduction of oxygen. However, the accumulation of an EPS film could stimulate the anodic dissolution of the underlying steel by chelation of Fe²⁺ ions.     

Microorganisms: Induction and inhibition of corrosion in metals

Corrosion occurs due to chemical or electrochemical reactions between the environment and metal. It can cause dangerous and expensive damage to a wide range of industries. However, it is difficult to evaluate the economic impact of corrosion, particularly when microorganisms are involved in the corrosion mechanism. Microbes change the electrochemical reaction at the biofilm/metal interface and either inhibit or accelerate the process of metal corrosion. The high cost, toxicity, and sometimes ineffectiveness of present physical and chemical strategies to control corrosion have called for the use of microorganisms in inhibitory mechanisms, and this has generated great interest. Although the microbial inhibitory mechanism is environmentally friendly, the predictability of the results is not yet affirmed, as sometimes the same bacteria with an inhibitory property may also become aggressive. This review discusses different mechanisms by which microbes induce or inhibit corrosion in metals. Further, as the corrosive or inhibiting behaviors of microorganisms vary considerably depending on environmental factors, the roles of these factors are also emphasized.     

Reduced secretion and expression of gelatinase profile in Toxoplasma gondii-infected human monocytic cells

The apicomplexan Toxoplasma gondii, an obligate intracellular parasite, can infect humans and a wide range of vertebrates. Following oral infection, the parasite invades tissues by crossing non-permissive biological barriers such as the placenta or the blood-brain barrier. But the molecular mechanisms underlying migration of T. gondii remain poorly characterized. The crossing of various basal membranes and infiltration into the extracellular matrix by T. gondii could involve matrix metalloproteinases (MMPs). We demonstrated a decrease in proMMP-2 and proMMP-9 secretion by THP-1 cells at 24 and 48h post invasion with regulation at the mRNA level throughout infection. This down regulation was associated with a decrease in TIMP-2 secretion and an inhibition of its expression. Moreover, results showed an activation of MT1-MMP; its expression was regulated after 6, 24, and 48h.     

Importance of biofilm formation for corrosion inhibition of SAE 1018 steel by axenic aerobic biofilms

To investigate if corrosion inhibition by aerobic biofilms is a general phenomenon, carbon steel (SAE 1018) coupons were exposed to a complex liquid medium (Luria–Bertani) and seawater-mimicking medium (VNSS) containing fifteen different pure-culture bacterial suspensions representing seven genera. Compared to sterile controls, the mass loss in the presence of these bacteria (which are capable of developing a biofilm to various degrees) decreased by 2- to 15-fold. The extent of corrosion inhibition in LB medium depended on the nature of the biofilm: an increased proportion of live cells, observed with confocal scanning laser microscopy (CSLM) and image analysis, decreased corrosion. Corrosion inhibition in LB medium was greatest with Pseudomonas putida (good biofilm formation), while metal coupons exposed to Streptomyces lividans in LB medium (poor biofilm formation) corroded in a manner similar to the sterile controls. Pseudomonas mendocina KR1 reduced corrosion the most in VNSS. It appears that only a small layer of active, respiring cells is required to inhibit corrosion, and the corrosion inhibition observed is due to the attached biofilm. Received 09 December 1996/ Accepted in revised form 19 March 1997     

油田硫酸盐还原菌酸化腐蚀机制及防治研究进展

硫酸盐还原菌(Sulfate reducing bacteria,SRB)是一些厌氧产硫化氢的细菌的统称,是以有机物为养料的厌氧菌。它们广泛分布于pH值6-9的土壤、海水、河水、淤泥、地下管道、油气井、港湾及锈层中,它们生存于好气性硫细菌产生的沉积物下,其最适宜的生长温度是20-30℃,可以在高达50-60℃的温度下生存,与腐蚀相关的最主要的是脱硫脱硫弧菌(Desulfovibrio desulfuricans)。 它们是许多腐蚀问题的主因,例如油田系统金属管路的腐蚀等。在海上油田生产中,海水常被注入油井用于进行2次采油。富含硫酸盐的海水能加速油藏中SRB的生长,随之H₂S大量产生,引起油田水的酸化,H₂S具有毒性和腐蚀性,增加石油和天然气中的硫含量,并可能引起油田堵塞。SRB引起的腐蚀问题是拭待解决的最主要问题。国内外治理该问题的途径主要有物理杀灭、添加化学杀菌剂等方法,但是这些方法成本高,持续效果不显著。近几年来国外学者开始重点关注利用生物竞争排斥技术(Bio-competitive inhibition technology,BCX)控制硫酸盐还原菌的生长代谢的方法,该方法的原理为通过加入特定的药剂,激活油藏中的本源微生物或加入外源微生物,使其与SRB竞争营养源或产生代谢物抑制SRB的生长代谢,进而抑制H₂S的产生。GMT-LATA的科学家对在厌氧油气储层和开采系统中硝酸盐还原菌的作用进行了最早的研究,认为该细菌可以抑制硫酸盐还原菌的代谢活动。随后BCX技术已经在国外部分油田得到了应用,国内还没有在海油生产中应用的报道,但是也有学者对该方法进行了研究。     

Corrosion of metals in natural waters influenced by manganese oxidizing microorganisms

Case histories and proposed mechanisms formicrobiologically influenced corrosion of metals andalloys by metal depositing microorganisms arereviewed. Mechanisms with indirect participation ofthese microorganisms, usually iron- and manganeseoxidizing species, are distinguished from anothermechanism which accounts specifically for theelectrochemical properties of deposits containingoxides and hydroxides of Mn in higher oxidationstates. The possible influence of such deposits whichwere formed microbiologically is evaluated. Theevaluation is based on the principles ofelectrochemical corrosion of metals and on theelectrochemical properties of Mn^3+/4+- compounds.After briefly reviewing the microbiologicalMn-oxidation, experimental evidence for the predictedcorrosion by such deposits is provided and a model formicrobiologically influenced corrosion by manganeseoxidizing microorganisms is proposed for stainlesssteel. Possible consequences of the model andpractical aspects of such a corrosion are discussed.     

Steel Anti-Corrosion Strategy Enables Long-Cycle Zn Anode

The progress of aqueous zinc batteries (AZBs) is limited by the poor cycling life due to Zn anode instability, including dendrite growth, surface corrosion, and passivation. Inspired by the anti-corrosion strategy of steel industry, a compounding corrosion inhibitor (CCI) is employed as the electrolyte additive for Zn metal anode protection. It is shown that CCI can spontaneously generate a uniform and ≈30 nm thick solid-electrolyte interphase (SEI) layer on Zn anode with a strong adhesion via Zn O bonding. This SEI layer efficiently prohibits water corrosion and guides homogeneous Zn deposition without obvious dendrite formation. This enables reversible Zn deposition and dissolution for over 1100 h under the condition of 1 mA cm⁻² and 1 mAh cm⁻² in symmetric cells. The Zn-MnO₂ full cells with CCI-modified electrolyte deliver an ultralow capacity decay rate (0.013% per cycle) at 0.5 A g⁻¹ over 1000 cycles. Such an innovative strategy paves a low-cost way to achieve AZBs with long lifespan.