脱氮硫杆菌生长特性及其对SRB生长的影响*

由土壤中分离得到一株自养型的脱氮硫杆菌 (Thiobacillusdenitrificans,硫杆菌属 ,硫杆菌科 ,革兰氏阴性化能自养细菌 ) ,该菌株的最佳生长 pH为 7 0。将此菌株与硫酸盐还原菌 (SulfateReducingBacteria ,SRB ,脱硫弧菌属 ,革兰氏阴性厌氧细菌 )混合培养 ,测定SRB的菌量变化 ,结果表明 ,脱氮硫杆菌的生长抑制了硫酸盐还原菌的生长 ,降低了SRB的腐蚀性的代谢产物硫化物的浓度 ,腐蚀速率降低 ,有利于防治SRB引起的微生物腐蚀。     

脱氮硫杆菌对硫酸盐还原菌生长的抑制作用

为了研究脱氮硫杆菌(Thiobacillus denitrificans,TDN)对硫酸盐还原菌(sulfate-reducing bacteria,SRB)生长的影响,将从污水中分离到的硫酸盐还原菌和从pH为2~3的酸性土壤中分离到的脱氮硫杆菌(TDN)用于含适当浓度硫酸盐和硝酸盐的模拟污水的处理,并测定单菌或混菌培养后系统中硫酸盐、硝酸盐浓度的变化以及硫化氢的产量。结果表明,在仅接种硫酸盐还原菌的培养系统中,硫酸盐和硝酸盐的含量分别降低4.8%和1.0%;而在同时接种脱氮硫杆菌和硫酸盐还原菌的系统中硫酸盐的含量升高了4.7%,但硝酸盐氮含量降低了25%,这一作用随着培养基中硝酸盐起始浓度的提高而得到加强。另外,混菌培养系统的硫化氢浓度比单一硫酸盐还原菌培养系统降低了65.93%。由此推断,在混菌培养系统中,脱氮硫杆菌通过其反硝化过程产生的代谢产物使硫酸盐还原菌的生长环境条件发生改变,从而抑制其生长并减少了硫化氢的产生。这对预防硫酸盐还原菌带来的不利影响提供了有效的措施。     

一株脱硫自养菌的分离与特性研究

从含硫土壤中分离到的一株无机化能自养型的脱氮硫杆菌菌株Ｌ１,该菌可利用硫代硫酸盐,硫酸盐作为能源,在细胞内,细胞外储存硫粒。在好所或厌气条件下,可以硝酸盐为氮源。最适生长ｐＨ６．０。在约１％接种量时,该菌于７天使硫代硫酸盐和硫酸盐的脱硫率分别达到３４．３７％和１９．７９％;混菌培养硫酸盐的转化率可达６６．７３％。     

一株脱氮硫杆菌的筛选及其脱氮除硫性能分析

利用人工模拟酸性环境,从定期浇注HCl的土壤中筛选出一株脱氮硫杆菌T1菌株,并对其生长特性以及pH、盐度等理化因素对其脱氮除硫性能的影响进行了研究。结果表明,该菌株最适生长pH为7.02,最适脱氮pH为7.0;培养基中NaCl含量低于1.5%时,其脱氮能力没明显变化;与硫酸盐还原菌混菌培养能将H2S氧化为SO42-,从而明显抑制H2S的产生。在液体静置混菌培养过程中,在培养开始后的24 h内,SO42-生成速率最大(11.21 mg/(L·h)),随后不断降低。该菌不仅适用于不同pH、盐度废水的生物处理,还可以与硫酸盐还原菌混合添加到厌氧消化池中以减少硫化物的形成,从而减轻后者对污水处理系统中的金属设备和管道的腐蚀作用以及硫化氢对大气的污染。     

一株中度嗜热嗜酸硫氧化杆菌的分离和系统发育分析

从云南腾冲温泉酸性水样分离得到一株中度嗜热嗜酸硫氧化杆菌MTH 0 4 ,对分离菌株进行了形态、生理生化特性研究及 1 6SrDNA序列分析。该菌株为革兰氏阴性细菌 ,短杆状 ,菌体大小 (0 6～ 0 8) μm× (1～ 2 ) μm ,化能自养 ,可利用硫磺、四硫酸盐、硫代硫酸盐为能源生长 ,不能利用蛋白胨、葡萄糖、酵母粉 ,也不能进行混合型生长。最适生长温度在 4 0℃～ 4 5℃之间 ,最适生长pH 2 0～ 3 0 ,代时 8h。以 1 6SrDNA序列同源性为基础构建了包括 1 3株相关种属在内的系统发育树 ,结果表明 ,MTH 0 4与喜温硫杆菌 (Thiobacilluscaldus)处于同一进化树分支中 ,相似性达 99 5 %以上     

一株嗜酸硫氧化菌的分离

从江西德兴分离得到一株嗜酸硫氧化杆菌DX-2,采用双层固体培养基进行分离纯化,对分离菌株进行了形态、生理生化特性研究及16SrRNA序列分析.该菌株为革兰氏阴性细菌,短杆状,菌体大小（0.4～0.5）μm×（1～2）μm,化能自养,可利用硫磺和硫代硫酸盐为能源生长,不能利用亚铁进行生长.以16SrRNA序列同源性为基础构建了相关种属在内的系统发育树,结果表明,DX-2与喜温硫杆菌（Acidithiobacillus caldus）处于同一进化树分支中,相似性达99%以上.考察了不同重金属离子对DX-2的生长的影响.     

锅炉管道回水、厌氧污泥中硫酸盐还原菌的筛选

目的研究硫酸盐还原菌及其筛选、分离鉴定体系.方法在锅炉管道回水和厌氧污泥中驯化、筛选硫酸盐还原能力强的菌株,以铬酸钡光度方法检测液体培养基中的硫酸根含量,测定了菌株的硫酸盐降解能力.结果在水样A和泥样B中,A1和B2菌株能够较好地降解培养基中的硫酸盐,通过计数得出A1和B2的最大可能菌数分别为1.65×10(6)个/ml、2.25×10(6)个/ml.并利用改进的稀释涂布-叠皿夹层培养方法分离鉴定A1和B2菌株,观察硫酸盐还原菌的形态,为进一步了解SRB的生长特性,进而从根本上解决硫酸盐还原菌腐蚀问题提供理论基础.结论经过实验,所筛选分离鉴定体系可行.     

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。     

硫代硫酸盐氧化菌TX的分离、鉴定及其生物学特性

从聚硫橡胶废水处理系统中分离到一株硫代硫酸盐氧化细菌TX.根据其形态学特征、生理特征和16S rRNA基因序列相似性分析,将该菌株初步鉴定为盐生硫杆菌属(Halothiobacillus sp.)(GenBank登录号为EU871645).该菌株能利用硫代硫酸盐、单质硫、连四硫酸盐、硫化物或亚硫酸盐为唯一能源进行自养生长,不能利用葡萄糖、蔗糖、果糖、乳糖、麦芽糖或酵母粉进行异养生长,为专性化能无机自养型硫杆菌.在以硫代硫酸钠为唯一能源的培养基中其最适生长温度为30℃～35℃,最适起始pH值为3.0～5.0.在矿物盐培养基中,硫代硫酸盐最终被氧化成硫酸,造成培养基pH持续下降.在摇瓶分批培养和硫胶废水处理过程中均检测到连四硫酸盐的积累,表明该菌株主要通过连四硫酸盐途径或"S4I"途径进行硫代硫酸盐的生物氧化.     

硫酸盐还原菌的分离筛选及鉴定

为了更好地利用硫酸盐还原菌(SRB)处理含重金属酸性废水,分离和筛选适宜的SRB菌株是需解决的首要问题。本研究从77个环境样品中分离纯化得到9株SRB菌株,其中5株菌通过16S rDNA序列的测序、比对,构建系统发育树,并结合形态学及生理生化特性进行分析,结果表明,5株菌都为脱硫弧菌属(Desulfovibrio)菌株,通过与Gen Bank中登录菌株比对,菌株SRB-6和SRB-8鉴定为脱硫脱硫弧菌,菌株SRB-4、SRB-12和SRB-15鉴定为Desulfovibrio oxamicus。对5株硫酸盐还原菌进行了还原硫酸盐的研究,菌株SRB-12还原能力最强,经60 h培养,可还原培养基中88.83%的硫酸盐。     

Mitigation of the corrosion-causing Desulfovibrio desulfuricans biofilm using an organic silicon quaternary ammonium salt in alkaline media simulated concrete pore solutions

Abstract

Organic silicon quaternary ammonium salt (OSA), an environmentally friendly naturally occurring chemical, was used as a bacteriostatic agent against sulphate-reducing bacteria (SRB) on a 20SiMn steel surface in simulated concrete pore solutions (SCP). Four different media were used: No SRB (NSRB), No SRB and OSA (NSRB?+?OSA), With SRB (WSRB), With SRB and OSA (WSRB?+?OSA). After biofilm growth for 28 days, optimized sessile SRB cells survived at the high pH of 11.35 and as a result these cells caused the breakdown of the passive film due to the metabolic activities of the SRB. Corrosion prevention results showed that the OSA was effective in mitigating the growth of the sessile SRB cells and reduced corrosion in the SCP. These results were further confirmed by scanning electron microscope images, energy dispersive X-ray analysis, confocal-laser scanning microscopy, X-ray photoelectron spectroscopy and corrosion testing using electrochemical analysis.     

脱氮硫杆菌的脱硫特性及其处理恶臭物质硫化氢的应用

污水和污泥的处理过程中会产生大量的恶臭气体硫化氢(H2S)。脱氮硫杆菌是氧化H2S和其他硫化物的重要的脱硫工程菌。本文阐述了脱氮硫杆菌的生物学特性和氧化H2S的两种途径。分析了反应体系中的硫化物负荷、硝酸盐和亚硝酸盐的浓度、氧含量以及pH值等因素对氧化效果、反应速率、氧化途径及产物形式的影响。介绍了脱氮硫杆菌在恶臭污染治理中的应用及其在同步处理含氮含硫恶臭物质方面的发展趋势。     

Importance of Hydrogen Sulfide, Thiosulfate, and Methylmercaptan for Growth of Thiobacilli during Simulation of Concrete Corrosion

Biogenic sulfuric acid corrosion of concrete surfaces caused by thiobacilli was reproduced in simulation experiments. At 9 months after inoculation with thiobacilli, concrete blocks were severely corroded. The sulfur compounds hydrogen sulfide, thiosulfate, and methylmercaptan were tested for their corrosive action. With hydrogen sulfide, severe corrosion was noted. The flora was dominated by Thiobacillus thiooxidans. Thiosulfate led to medium corrosion and a dominance of Thiobacillus neapolitanus and Thiobacillus intermedius. Methylmercaptan resulted in negligible corrosion. A flora of heterotrophs and fungi grew on the blocks. This result implies that methylmercaptan cannot be degraded by thiobacilli.     

Oxidation of hydrogen sulfide by Thiobacilli

It has been previously demonstrated that the chemoautotroph and facultative anaerobe, Thiobacillus denitrificans, may be cultured aerobically or anaerobically in batch and continuous reactors on H(2)S(g) under sulfide-limiting conditions. A process has been proposed for the removal of H(2)S from gases based on oxidation of H(2)S by T. denitrificans. Described here is a study of H(2)S oxidation by other Thiobacilli, the purpose of which has been to determine whether other Thiobacilli offer any advantages over T. denitrificans in the aerobic oxidation of H(2)S. Although four other species of Thiobacillus were found to grow on H(2)S as an energy source, none offer a clear advantage over T. denitrificans.     

Inhibiting sulfate-reducing bacteria in biofilms on steel with antimicrobial peptides generated in situ

In batch and continuous fermentations, the reduction in corrosion of SAE 1018 mild steel and 304 stainless steel caused by inhibition of the reference sulfate-reducing bacterium (SRB) Desulfovibrio vulgaris by a protective, antimicrobial-producing Bacillus brevis biofilm was investigated. The presence of D. vulgaris produced a thick black precipitate on mild steel and a higher corrosion rate in batch cultures than that seen in a mono-culture of non-antimicrobial-producing Pseudomonas fragi K upon the addition of SRB to the aerobic P. fragi K biofilm. In continuous reactors, the polarization resistance R _p decreased for stainless steel and increased for mild steel upon the addition of SRB to a P. fragi K biofilm. Addition of either 200 μg/ml ampicillin, chloramphenicol, or ammonium molybdate to batch and continuous reactors after SRB had colonized the metal was ineffective in killing SRB, as inferred from the lack of change in both R _p and the impedance spectra. However, when ampicillin was added prior to SRB colonization, the growth of SRB was completely inhibited on stainless steel in continuous reactors. Prior addition of ampicillin was only able to delay the growth of SRB on mild steel in continuous reactors. External addition of the purified peptide antimicrobial agent gramicidin S prior to the addition of SRB also inhibited the growth of SRB on stainless steel in continuous reactors, and the SRB were also inhibited on stainless steel in both batch and continuous reactors by producing gramicidin S in situ in a protective biofilm when the gramicidin-S-overproducing strain Bacillus brevis 18 was used. Received: 29 October 1998 / Received revision: 18 February 1999 / Accepted: 26 February 1999     

Nitrate promotes biological oxidation of sulfide in wastewaters: experiment at plant-scale

Biogenic production of sulfide in wastewater treatment plants involves odors, toxicity and corrosion problems. The production of sulfide is a consequence of bacterial activity, mainly sulfate-reducing bacteria (SRB). To prevent this production, the efficiency of nitrate addition to wastewater was tested at plant-scale by dosing concentrated calcium nitrate (Nutriox) in the works inlet. Nutriox dosing resulted in a sharp decrease of sulfide, both in the air and in the bulk water, reaching maximum decreases of 98.7% and 94.7%, respectively. Quantitative molecular microbiology techniques indicated that the involved mechanism is the development of the nitrate-reducing, sulfide-oxidizing bacterium Thiomicrospira denitrificans instead of the direct inhibition of the SRB community. Denitrification rate in primary sedimentation tanks was enhanced by nitrate, being this almost completely consumed. No significant increase of inorganic nitrogen was found in the discharged effluent, thus reducing potential environmental hazards to receiving waters. This study demonstrates the effectiveness of nitrate addition in controlling sulfide generation at plant-scale, provides the mechanism and supports the environmental adequacy of this strategy.     

Impact of nitrate-mediated microbial control of souring in oil reservoirs on the extent of corrosion

The effect of microbial control of souring on the extent of corrosion was studied in a model system consisting of pure cultures of the nitrate-reducing, sulfide-oxidizing bacterium (NR-SOB) Thiomicrospira sp. strain CVO and the sulfate-reducing bacterium (SRB) Desulfovibrio sp. strain Lac6, as well as in an SRB consortium enriched from produced water from a Canadian oil reservoir. The average corrosion rate induced by the SRB consortium (1.4 g x m(-2) x day(-1)) was faster than that observed in the presence of strain Lac6 (0.2 g x m(-2) x day(-1)). Examination of the metallic coupons at the end of the tests indicated a uniform corrosion in both cases. Addition of CVO and 10 mM nitrate to a fully grown culture of Lac6 or the SRB consortium led to complete removal of sulfide from the system and a significant increase in the population of CVO, as determined by reverse sample genome probing. In the case of the SRB consortium addition of just nitrate (10 mM) had a similar effect. When grown in the absence of nitrate, the consortium was dominated by Desulfovibrio sp. strains Lac15 and Lac29, while growth in the presence of nitrate led to dominance of Desulfovibrio sp. strain Lac3. The addition of CVO and nitrate to the Lac6 culture or nitrate to the SRB consortium accelerated the average corrosion rate to 1.5 and 2.9 g x m(-2) x day(-1), respectively. Localized corrosion and the occurrence of pitting were apparent in both cases. Although the sulfide concentration (0.5-7 mM) had little effect on corrosion rates, a clear increase of the corrosion rate with increasing nitrate concentration was observed in experiments conducted with consortia enriched from produced water.     

Oxidation of hydrogen sulfide by flocculated Thiobaccillus denitrificans in a continuous culture

In a continuous fermentation, significant advantages may be gained by immobilization of microbial cells. Immobilization allows cells to be retained in the fermenter or to be readily recovered and recycled. Therefore, the hydraulic retention time and the biomass retention time are decoupled. A novel cell immobilization has been developed for the immobilization of autotrophic bacteria by coculture with floc-forming heterotrophic bacteria with growth of the latter limited by the availability of organic carbon. The result is an immobilization matrix which grows along with the immobilized autotroph. We have previously demonstrated the utility of this approach by immobilizing the chemoautotroph Thiobacillus denitrificans in macroscopic floc by coculture with floc-forming heterotrophs from an activated sludge treatment facility. Floc with excellent settling characteristics were produced. These floc have now been used to remove H(2)S from a gas stream bubbled through continuous cultures. The stoichiometry and kinetics of H(2)S oxidation by immobilized T. denitrificans were comparable to that reported previously for free-cell cultures. Oxygen uptake measurements indicated the growth of both T. denitrificans and the heterotrophs although the medium contained no added organic carbon. Continuous cultures with total biomass recycle were maintained for up to four months indicating the long-term stability of the commensal relationship between the immobilized autotroph and the heterotrophs which composed the immobilization matrix. It was observed that at any given H(2)S loading the biomass concentration reached a maximum and leveled out. The ultimate biomass concentration was dependent upon the H(2)S feed rate.     

Inhibiting mild steel corrosion from sulfate-reducing bacteria using antimicrobial-producing biofilms in Three-Mile-Island process water

Biofilms were used to produce gramicidin S (a cyclic decapeptide) to inhibit corrosion-causing, sulfate-reducing bacteria (SRB). In laboratory studies these biofilms protected mild steel 1010 continuously from corrosion in the aggressive, cooling service water of the AmerGen Three-Mile-Island (TMI) nuclear plant, which was augmented with reference SRB. The growth of both reference SRB (Gram-positive Desulfosporosinus orientis and Gram-negative Desulfovibrio vulgaris) was shown to be inhibited by supernatants of the gramicidin-S-producing bacteria as well as by purified gramicidin S. Electrochemical impedance spectroscopy and mass loss measurements showed that the protective biofilms decreased the corrosion rate of mild steel by 2- to 10-fold when challenged with the natural SRB of the TMI process water supplemented with D. orientis or D. vulgaris. The relative corrosion inhibition efficiency was 50–90% in continuous reactors, compared to a biofilm control which did not produce the antimicrobial gramicidin S. Scanning electron microscope and reactor images also revealed that SRB attack was thwarted by protective biofilms that secrete gramicidin S. A consortium of beneficial bacteria (GGPST consortium, producing gramicidin S and other antimicrobials) also protected the mild steel.     

Assessment of the addition of Thiobacillus denitrificans and Thiomicrospira denitrificans to chemolithoautotrophic denitrifying bioreactors

The aim of the present study was to assess the impact of adding cultures of Thiobacillus denitrificans and Thiomicrospira denitrificans to two upflow anaerobic sludge bed (UASB) reactors: one inoculated with granular sludge and the other filled only with activated carbon (AC). The performances of the bioreactors and the changes in biomass were compared with a non-bioaugmented control UASB reactor inoculated with granular sludge. The reactors inoculated with granular sludge achieved efficiencies close to 90% in nitrate and thiosulfate removal for loading rates as high as 107 mmol-NO3 -/l per day and 68 mmol-S2O3 2-/l per day. Bioaugmentation with Tb. denitrificans and Tm. denitrificans did not enhance the efficiency compared to that achieved with non-bioaugmented granular sludge. The loading rates and efficiencies were 30-40% lower in the AC reactor. In all the reactors tested, Tb. denitrificans became the predominant species. The results strongly suggest that this bacterium was responsible for denitrification and sulfoxidation within the reactors. We additionally observed that granules partially lost their integrity during operation under chemolithoautotrophic conditions, suggesting limitations for long-term operation if bioaugmentation is applied in practice.