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Microbial degradation of carbonyl sulfide, a trace sulfur gas in atmosphere, and the distribution of carbonyl sulfide-degraders in soil environments

大气中微量含硫气体硫化羰的微生物降解及土壤环境中硫化羰降解剂的分布

基本信息

批准号：
18310020
负责人：
YOKO Katayama
金额：
$ 10.71万
依托单位：
Tokyo University of Agriculture and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

Carbonyl sulfide (COS) is the most abundant sulfur compound in the atmosphere, with its tropospheric mixing ratios reported to be around 500 pptv. COS is regarded as a dominant source of stratospheric sulfate aerosol, which influences the earth's radiation budget, and then the climate. Therefore, attention is being focused on both sources and sinks of COS. Although sail microorganisms are known to play a role as a sink for atmospheric COS, little information is available on the quantification of microorganisms responsible for the COS degradation.COS added to the liquid culture is abiotically degraded to carbon dioxide and hydrogen sulfide during incubation period, and co-metabolic transformation might be significant in the case of consumption of atmospheric trace gas. Therefore, MPN was diverted as follows: we counted MPN of chemoorganotrophic microorganisms first, then presence of the COS-degrading microbes were confirmed by using the culture of the MPN. COS gas was added to each cult … More ure after 1-2 week's incubation of MPN for chemoorganotrophs, and COS decrease was monitored by FPD-GC.Densities of chemoorganotrophs and COS degraders were 1.0 x 10^7 and 3.5 x 10^6 MPN/g d. w., respectively, in a forest soil which degraded 30 ppmv of COS in one hour, indicating that COS degraders accounted for the large part of chemooarganotrophic microorganisms. Comparative 16S rRNA gene sequence analysis indicated that these isolates belonged to the genera Mycobacterium, Williamsia and Cupriavidus. For example, Mycobacterium sp. strain THI401, grown on PYG agar medium, was able to degrade an initial 30 ppmv COS within one hour, while 60% of the initial COS was decreased by abiotic conversion in 30 hours. Considering natural COS flux between sail and the atmosphere, COS degradation by these bacteria was confirmed at an ambient level of 500 pptv using sterilized soil to cultivate the bacterium: Strain THI401 degraded COS from an initial level of 530 pptv to a level of 330 pptv in 30 hours. These results provide experimental evidence of microbial activity in soil as a sink for atmospheric COS. By using crude extract of strain THI401, COS hydrolase was purified to 17 fold of the original by column chromatography. COS hydrolase has been purified from Thiobacillus thioparus THI115, a chemolithoautotrophic COS degrading bacterium. Cloning of the gene was conducted based on the amino acid sequence data of N-terminal COS hydrolase, and open reading flame of 660 by was determined. COS hydrolase is found to be encoded by a single gene in strain THI115. Less

羰基硫（COS）是大气中最丰富的硫化合物，据报道其对流层混合比约为500 pptv。COS被认为是平流层硫酸盐气溶胶的主要来源，它影响地球的辐射收支，进而影响气候。因此，人们的注意力集中在COS的源和汇上。虽然已知帆微生物作为大气COS的汇发挥作用，但很少有信息可用于对负责COS降解的微生物的量化。COS添加到液体培养物在培养期间被非生物降解为二氧化碳和硫化氢，并且在消耗大气痕量气体的情况下，共代谢转化可能是显著的。因此，MPN如下转向：我们首先计数化学有机营养微生物的MPN，然后通过使用MPN的培养物来确认COS降解微生物的存在。COS气体被添加到每个培养物中， ...更多信息在MPN培养1-2周后，COS的降解率下降，化学有机营养菌和COS降解菌的密度分别为1.0 × 10^7和3.5 × 10^6 MPN/g·d。W.，在1 h内降解30 ppmv COS的森林土壤中，COS降解菌占很大比例。比较16 S rRNA基因序列分析表明，这些菌株属于分枝杆菌属，威廉属和贪铜菌属。例如，生长在PYG琼脂培养基上的分枝杆菌属菌株THI 401能够在1小时内降解初始30 ppmv COS，而在30小时内通过非生物转化降低60%的初始COS。考虑到帆和大气之间的天然COS通量，使用灭菌土壤培养细菌，在500 pptv的环境水平下证实了这些细菌对COS的降解：菌株THI 401在30小时内将COS从530 pptv的初始水平降解到330 pptv的水平。这些结果为土壤作为大气COS汇的微生物活性提供了实验证据。以THI 401粗提物为原料，经柱层析纯化，COS水解酶的纯度提高了17倍。从化能自养COS降解菌ThiobacillusthioparusTHI 115中分离纯化了COS水解酶。根据N-末端COS水解酶的氨基酸序列数据进行了该基因的克隆，并确定了660 bp的开放阅读火焰。发现COS水解酶由菌株THI 115中的单个基因编码。少