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

羰基硫化物(COS)是大气中含量最丰富的硫化物，据报道其对流层混合比约为500PPTV。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，人们对COS的源和汇都很关注。尽管SAIL微生物被认为是大气中COS的汇，但对导致COS降解的微生物的量化信息很少。添加到液体培养物中的COS在培养期间被非生物降解为二氧化碳和硫化氢，在消耗大气微量气体的情况下，共代谢转化可能是重要的。因此，我们对MPN进行了如下转移：首先对化学有机营养微生物的MPN进行计数，然后通过MPN的培养来证实COS降解菌的存在。因为气体被添加到每个邪教…在1小时内降解30ppmv COS的森林土壤中，化学有机质和COS降解菌的密度分别为1.0×10~(-7)和3.5×10~(-6)MPN/g·d·w，表明COS降解菌占化学有机质营养微生物的大部分。16S rRNA基因序列比较分析表明，这些菌株属于分枝杆菌属、威廉斯属和铜绿假单胞菌属。例如，分枝杆菌属。在PYG琼脂上生长的菌株THI401能够在1小时内降解30ppmv的初始COS，而在30小时内非生物转化使初始COS的降解率达到60%。考虑到船帆和大气之间的自然COS通量，利用灭菌土壤培养该细菌，证实了这些细菌在环境水平500PPTV下对COS的降解：菌株THI401在30小时内将COS从最初的530 PPTV降解到330 PPTV。这些结果为土壤中微生物作为大气COS汇的活性提供了实验证据。利用菌株THI401的粗提液，用柱层析法将COS水解酶纯化到原来的17倍。从化学自养COS降解菌THI115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进行克隆，并测定其660的开放读数火焰。在菌株THI115中发现CoS水解酶由单基因编码。较少

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