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硫氧化细菌的种类及硫氧化途径的研究进展 总被引:3,自引:0,他引:3
硫,作为生物必需的大量营养元素之一,参与了细胞的能量代谢与蛋白质、维生素和抗生素等物质代谢。自然界中,硫以多种化学形态存在,包括单质硫、还原性硫化物、硫酸盐和含硫有机物。硫氧化是硫元素生物地球化学循环的重要组成部分,通常是指单质硫或还原性硫化物被微生物氧化的过程。硫氧化细菌种类繁多,其硫氧化相关基因、酶和途径也多种多样。近几年,相关方面的研究已取得很多进展,但在不同层面仍存在一些尚未解决的科学问题。本文主要围绕硫氧化细菌的种类及硫氧化途径的研究进展进行了综述。 相似文献
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随着世界各国对保护环境的意识不断增加,环境中有害的硫逐渐增多。传统的脱硫方法工艺复杂,成本高,会造成二次污染等问题,生物脱硫技术成为石油脱硫领域的新的研究热点之一。本文从生物脱硫技术的特点,筛选出高效的脱硫菌株,脱硫的途径,国内外研究的现状及发展进行综述。 相似文献
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【目的】从生物脱硫脱氮EGSB-DSR反应器的污泥中分离筛选出具有生物脱硫脱氮特性的细菌,并对其生物脱硫脱氮的性能进行研究。【方法】采用Hungate厌氧滚管技术筛选功能微生物,从稳定运行的生物脱硫脱氮EGSB-DSR反应器的污泥中分离筛选出一株高效的生物脱硫脱氮细菌A2。【结果】经过16S rRNA基因序列鉴定,菌株A2为固氮弧菌属(Azoarcus sp.)。其典型特征为能够以有机碳作为电子供体,将亚硝酸盐或者硝酸盐转化为氮气的同时还能将硫化物氧化为硫单质。因此具备了高效同步代谢有机碳、NO3–和S2–的特征。这是首次关于固氮弧菌属能够进行反硝化脱硫的相关报道。对菌株A2的生物脱硫脱氮能力的分析表明,在硫化物S2–浓度200 mg/L,NO3?浓度87.5 mg/L,乙酸根离子浓度200 mg/L的条件下,菌株A2在20 h内完成对碳、氮、硫的脱除。菌株对于碳、氮去除率均达到99%,对于硫的去除率达到95%。【结论】结果表明固氮弧菌属A2具有高效的生物脱硫脱氮功能,将有望成为强化生物脱硫脱氮工艺的潜在微生物资源。 相似文献
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细菌脱有机硫的遗传学研究进展* 总被引:5,自引:0,他引:5
化石燃料的燃烧,产生大量的有毒气体SO2进入大气,造成严重的空气污染,同时也是产生酸雨的最主要的原因[1,9]。为了保护环境,要求使用低硫含量的化石燃料,但目前世界上低硫含量的化石燃料储备正在急剧减少。因此需要对含硫高的化石燃料进行脱硫处理。化学脱硫方法一加氢脱硫(Hydrodesulfurization)难以脱去化石燃料中的有机硫。而生物催化法脱硫便宜,在常温下即可进行,并且具有高专一性,因此发展一种化石燃料的生物脱硫方法已是十分必要[1]。 化石燃料中的有机硫主要是二苯并噻吩(Dibenzothiophene,DBT),于是生物脱… 相似文献
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硫氧化细菌源单质硫的生成、转运和回收 总被引:1,自引:0,他引:1
单质硫(硫粒)是硫化物生物氧化的中间产物.按化学计量式精准调控O/S比(溶解氧与硫化物的摩尔比),单质硫可成为硫氧化细菌(Sulfur-oxidizing bacteria,SOB)的主要代谢产物.根据单质硫的分布,单质硫可分为胞内硫粒和胞外硫粒.单质硫由胞内向胞外的跨膜转运过程是泌硫型SOB的重要生理特征.从生物脱硫... 相似文献
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Olga Martzoukou Diomi Mamma Dimitris G. Hatzinikolaou 《Biotechnology and bioengineering》2023,120(10):3092-3098
Microbial desulfurization has been extensively studied as a promising alternative to the widely applied chemical desulfurization process. Sulfur removal from petroleum and its products becomes essential, as the environmental regulations become increasingly stringent. Rhodococcus qingshengii IGTS8 has gained ground as a naturally occurring model biocatalyst, due to its superior specific activity for desulfurization of dibenzothiophene (DBT). Recalcitrant organic sulfur compounds—DBT included—are preferentially removed by selective carbon-sulfur bond cleavage to avoid a reduction in the calorific value of the fuel. The process, however, still has not reached economically sustainable levels, as certain limitations have been identified. One of those bottlenecks is the repression of catalytic activity caused by ubiquitous sulfur sources such as inorganic sulfate, methionine, or cysteine. Herein, we report an optimized culture medium for wild-type stain IGTS8 that completely alleviates the sulfate-mediated repression of biodesulfurization activity without modification of the natural biocatalyst. Medium C not only promotes growth in the presence of several sulfur sources, including DBT, but also enhances biodesulfurization of resting cells grown in the presence of up to 5 mM sulfate. Based on the above, the present work can be considered as a step towards the development of a more viable commercial biodesulfurization process. 相似文献
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Grossman MJ Lee MK Prince RC Minak-Bernero V George GN Pickering IJ 《Applied and environmental microbiology》2001,67(4):1949-1952
Dibenzothiophene (DBT), and in particular substituted DBTs, are resistant to hydrodesulfurization (HDS) and can persist in fuels even after aggressive HDS treatment. Treatment by Rhodococcus sp. strain ECRD-1 of a middle distillate oil whose sulfur content was virtually all substituted DBTs produced extensive desulfurization and a sulfur level of 56 ppm. 相似文献
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Deep Desulfurization of Extensively Hydrodesulfurized Middle Distillate Oil by Rhodococcus sp. Strain ECRD-1 总被引:1,自引:0,他引:1 下载免费PDF全文
M. J. Grossman M. K. Lee R. C. Prince V. Minak-Bernero G. N. George I. J. Pickering 《Applied microbiology》2001,67(4):1949-1952
Dibenzothiophene (DBT), and in particular substituted DBTs, are resistant to hydrodesulfurization (HDS) and can persist in fuels even after aggressive HDS treatment. Treatment by Rhodococcus sp. strain ECRD-1 of a middle distillate oil whose sulfur content was virtually all substituted DBTs produced extensive desulfurization and a sulfur level of 56 ppm. 相似文献
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Improvement of biodesulfurization rate by assembling nanosorbents on the surfaces of microbial cells 总被引:1,自引:0,他引:1 下载免费PDF全文
To improve biodesulfurization rate is a key to industrialize biodesulfurization technology. The biodesulfurization rate is partially affected by transfer rate of substrates from organic phase to microbial cell. In this study, gamma-Al2O3 nanosorbents, which had the ability to selectively adsorb dibenzothiophene (DBT) from organic phase, were assembled on the surfaces of Pseudomonas delafieldii R-8 cell, a desulfurization strain. gamma-Al2O3 nanosorbents have the ability to adsorb DBT from oil phase, and the rate of adsorption was far higher than that of biodesulfurization. Thus, DBT can be quickly transferred to the biocatalyst surface where nanosorbents were located, which quickened DBT transfer from organic phase to biocatalyst surface and resulted in the increase of biodesulfurization rate. The desulfurization rate of the cells assembled with nanosorbents was approximately twofold higher than that of original cells. The cells assembled with nanosorbents were observed by a transmission electron microscope. 相似文献
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Rhodococcus erythropolis has been studied widely for potential applications in biodesulfurization. Previous works have been largely experimental with an emphasis on the characterization and genetic engineering of desulfurizing strains for improved biocatalysis. A systems modeling approach that can complement these experimental efforts by providing useful insights into the complex interactions of desulfurization reactions with various other metabolic activities is absent in the literature. In this work, we report the first attempt at reconstructing a flux-based model to analyze sulfur utilization by R. erythropolis. The model includes the 4S pathway for dibenzothiophene (DBT) desulfurization. It predicts closely the growth rates reported by two independent experimental studies, and gives a clear and comprehensive picture of the pathways that assimilate the sulfur from DBT into biomass. In addition, it successfully elucidates that sulfate promotes higher cell growth than DBT and its presence in the medium reduces DBT desulfurization rates. A study using eight carbon sources suggests that ethanol and lactate yield higher cell growth and desulfurization rates than citrate, fructose, glucose, gluconate, glutamate, and glycerol. 相似文献
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Desulfurization of Dibenzothiophene and Diesel Oils by a Newly Isolated Gordona Strain, CYKS1 总被引:8,自引:0,他引:8 下载免费PDF全文
Sung-Keun Rhee Je Hwan Chang Yong Keun Chang Ho Nam Chang 《Applied microbiology》1998,64(6):2327-2331
A dibenzothiophene (DBT)-desulfurizing bacterial strain was isolated and identified as Gordona strain CYKS1. Strain CYKS1 was found to transform DBT to 2-hydroxybiphenyl via the 4S pathway and to be able to also use organic sulfur compounds other than DBT as a sole sulfur source. Its desulfurization activity was susceptible to sulfate repression. Active resting cells for desulfurization could be prepared only in the early growth phase. When two types of diesel oils, middle distillate unit feed (MDUF) and light gas oil (LGO) containing various organic sulfur compounds including DBT, were treated with resting cells of strain CYKS1 for 12 h, the total sulfur content significantly decreased, from 0.15% (wt/wt) to 0.06% (wt/wt) for MDUF and from 0.3% (wt/wt) to 0.25% (wt/wt) for LGO. The newly isolated strain CYKS1 is considered to have good potential for application in the biodesulfurization of fossil fuels. 相似文献
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Various heterocyclic sulfur compounds such as naphtho[2,1-b]thiophene (NTH) and benzo[b]thiophene (BTH) derivatives can be detected in diesel oil, in addition to dibenzothiophene (DBT) derivatives. Mycobacterium phlei WU-0103 was newly isolated as a bacterial strain capable of growing in a medium with NTH as the sulfur source at 50°C. M. phlei WU-0103 could degrade various heterocyclic sulfur compounds, not only NTH and its derivatives but also DBT, BTH, and their derivatives at 45°C. When M. phlei WU-0103 was cultivated with the heterocyclic sulfur compounds such as NTH, NTH 3,3-dioxide, DBT, BTH, and 4,6-dialkylDBTs as sulfur sources, monohydroxy compounds and sulfone compounds corresponding to starting heterocyclic sulfur compounds were detected by gas chromatography–mass spectrometry analysis, suggesting the sulfur-specific desulfurization pathways for heterocyclic sulfur compounds. Moreover, total sulfur content in 12-fold-diluted crude straight-run light gas oil fraction was reduced from 1000 to 475 ppm S, with 52% reduction, by the biodesulfurization treatment at 45°C with growing cells of M. phlei WU-0103. Gas chromatography analysis with a flame photometric detector revealed that most of the resolvable peaks, such as those corresponding to alkylated derivatives of NTH, DBT, and BTH, disappeared after the biodesulfurization treatment. These results indicated that M. phlei WU-0103 may have a good potential as a biocatalyst for practical biodesulfurization of diesel oil. 相似文献
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Rhodococcus erythropolis has been widely studied for desulfurization. However, activity levels required for commercial application have not been achieved. A major limitation of the current work in biodesulfurization is inadequate information regarding sulfur metabolism generally, and in particular the metabolism of the sulfur obtained from dibenzothiophene (DBT) metabolism via the 4S pathway. In this work, we have investigated the possible routes taken by the sulfur from DBT to convert into biomass or other metabolites. We propose two alternate hypotheses. In the first, we hypothesize that the cell can convert via sulfite reductase (SR) the sulfite from the metabolism of DBT into sulfide that can be assimilated into biomass. However, in the process, it may convert any excess sulfite into extracellular sulfate via sulfite oxidoreductase (SOR) to avoid the toxic effects of sulfite. In the second, we speculate that the cell cannot assimilate the sulfite directly into biomass via SR. It must first use SOR to produce extracellular sulfate, and then recapture that sulfate into biomass via SR. Thus, either way, we propose that SOR and SR activities, in addition to dsz genes and cofactors, may be critical in increasing desulfurization levels significantly. In particular, we suggest that the simultaneous increase in SOR activity and decrease in SR activity can enable increased desulfurization activity. 相似文献
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脱硫工程菌的构建及其脱硫性能分析 总被引:1,自引:0,他引:1
以专一性脱硫菌德氏假单胞菌Pseudomonas delafieldii R-8为出发菌株, 利用pPR9TT穿梭质粒构建脱硫操纵子表达载体, 转化原始菌培养得到1株多拷贝脱硫基因的脱硫工程菌R-8-1, 并对其脱硫性能进行了研究。结果表明, 在同样的生物催化脱硫反应条件下, 工程菌的脱硫活性达到6.25 mmol DBT/g dry cell/h, 是原始菌的2倍; 柴油的脱硫试验表明, 在12 h内工程菌静息细胞能将柴油硫含量从310.8 mg/L降至100.1 mg/ L, 脱硫率达到68%, 而原始菌为53%。进一步比较了重组质粒pPR-dsz在工程菌株中传代的稳定性, 试验表明pPR-dsz在工程菌株R-8-1中具有良好的遗传稳定性。此研究为生物脱硫提供了1株优良的工程菌株, 并为该技术的应用提供了参考。 相似文献
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Biodesulfurization is regarded as a promising alternative technology for desulfurization from diesel oil due to its mild operating conditions and its ability to remove sulfur from alky dibenzothiophenes (Cx-DBTs). The diesel oil contains complex mixtures of Cx-DBTs in which individual microbial biodesulfurization may be altered. In this work, interactions among three typical Cx-DBTs such as dibenzothiophenes (DBT), 4-methyldibenzothiophene (4-MDBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) were investigated using Mycobacterium sp. ZD-19 in an airlift reactor. The experimental results indicated that the desulfurization rates would decrease in the multiple Cx-DBTs system compared to the single Cx-DBT system. The extent of inhibition depended upon the substrate numbers, concentrations, and affinities of the co-existing substrates. For example, compared to individual desulfurization rate (100 %), DBT desulfurization rate decreased to 75.2 % (DBT + 4,6-DMDBT), 64.8 % (DBT + 4-MDBT), and 54.7 % (DBT + 4,6-DMDBT + 4-MDBT), respectively. This phenomenon was caused by an apparent competitive inhibition of substrates, which was well predicted by a Michaelis–Menten competitive inhibition model. 相似文献