Microbial Degradation of n-Alkyl Tetrahydrothiophenes Found in Petroleum

[This corrects the article on p. 1245 in vol. 54.].     

鼠李糖脂对微生物降解石油烃废水的影响

目的:研究鼠李糖脂对微生物降解石油烃废水的影响.方法:通过测定生物量和观察菌株表面来研究鼠李糖脂对菌株的影响;通过正交实验设计,确定石油烃降解率影响因素.通过石油烃降解率的测定,探讨鼠李糖脂与H2O2深度氧化协同作用对微生物降解石油烃的影响.结果:菌株对石油烃的降解率达53%,在相同条件下,添加鼠李糖脂的石油烃降解率提高了12%-20%.添加鼠李糖脂后菌株的生物量明显增多,菌株细胞表面疏水.正交设计表明,影响石油烃降解的主导因子是培养温度,其次是培养时间和鼠李糖脂的添加量.正交设计得到最佳组合为A3B2C1,即培养时间为7d;温度为35℃,鼠李糖脂浓度为60mg/L.3个因素的最佳组合下,石油烃降解率为82%.加入200 mg/L的H2O2时,降解率从82%提高到97%.结论:鼠李糖脂能促进菌株的生长.鼠李糖脂与H2O2深度氧化协同作用有助于微生物对石油烃类污染物降解效率的提高.     

一株假单胞菌HZ-1降解石油烃的初步研究

从石油废水活性污泥中分离到一株可以较好降解石油烃的假单胞菌（Pseudomonas sp）HZ-1,采用生物膜法对该菌株在30℃条件下降解某炼油厂废水中的烃类物质进行了研究.研究结果表明不同营养盐NH4NO3、NaH2PO4、NH4Cl对菌株HZ-1处理石油废水的作用不同,终浓度为1000mg/L的NH4NO3对菌株HZ-1处理石油废水效果最佳.并在30℃和pH 8.0的条件下,初步研究了该菌株降解萘的情况,在萘浓度低于78 mg/L的情况下,120 rpm好氧振荡培养144h,这株菌对萘的降解率在86%以上.     

石油烃类的微生物降解

石油作为重要能源之一已被世界各国广泛使用,由于在石油的开采、储存、运输、加工和石化产品生产等过程中的漏油以及突发性泄油事故致使大量的石油进入环境造成污染。石油污染的危害主要表现在对土壤生态系统的结构和功能的破坏,严重影响土壤的透气性和渗水性,导致土壤板结、肥力下降;在水体表面形成油膜,致使水中溶氧量急剧下降,造成水生生物的大量死亡,破坏水生生态环境和渔业资源;还可进入地下水系,直接污染地下水源,影响居民用水和农田灌溉;石油中的一些致畸致癌物质还可通过食物链的生物富集作用而直接危害人类健康。随着人们对环境问题的日益关注,石油烃类的微生物降解研究工作也不断得以深入。近十年来这一领域又有许多研究和相关报道,本文对相关工作进行了综述。     

Degradation of Petroleum by an Alga, Prototheca Zopfii

Prototheca zopfii is an achlorophyllous alga which degrades oil. It has been found to degrade 10 and 40% of a motor oil and crude oil, respectively, when tested under appropriate conditions. Degradation of the crude oil observed in this study compares well with the amount of degradation accomplished by bacteria. P. zopfii was found to degrade a greater percentage of the aromatic hydrocarbons in motor oil than of the saturated hydrocarbons and a greater percentage of saturated hydrocarbons in crude oil than of aromatic hydrocarbons. Resins and asphaltens were produced during degradation of motor oil, whereas these fractions in crude oil were degraded. P. zopfii did not demonstrate preferential utilization of lower homologues of cycloalkanes and aromatics as has been observed with bacteria.     

Microbial Degradation of Asphalt

Organisms of the genera Pseudomonas, Chromobacterium, and Bacillus capable of degrading asphalt were isolated by enrichment cultures. The asphalt degradation by these organisms varied from 3 to 25% after incubation for 1 week. The effects of temperature, pH, and atmosphere of incubation on asphalt degradation were investigated and were shown to vary with different organisms on the same substrate.     

Microbial Degradation of Octamethylcyclotetrasiloxane

The microbial degradation of low-molecular-weight polydimethylsiloxanes was investigated through laboratory experiments. Octamethylcyclotetrasiloxane was found to be biodegraded under anaerobic conditions in composted sewage sludge, as monitored by the occurrence of the main polydimethylsiloxane degradation product, dimethylsilanediol, compared to that found in experiments with sterilized control samples.     

Microbial Degradation of Sterols

A process is described for the microbial degradation of cholesterol and plant sterols, to produce androsta-1, 4-diene-3, 17-dione and androst-4-ene-3, 17-dione, by two newly isolated bacteria designated Mycobacterium sp. NRRL B-3683 and Mycobacterium sp. NRRL B-3805. These myocbacteria produce substantial amounts of 17-ketonic compounds without appreciable degradation of the steroid nucleus. No ring degradation inhibitory agents are necessary. The first microbiological production of 20alpha-hydroxymethylpregna-1, 4-dien-3-one is also reported.     

Microbial Degradation of Bergenia,a Phenolic C-Glucoside

A strain of soil bacteria was isolated by elective culture with bergenia, a C-glucoside having dihydroisocoumarin structure, as a sole carbon source, and was identified as Erwinia herbicola. In growth or replacement medium, the bacterium degraded bergenin to yield at least two major degradation products, one of them being identified as 4-O-methylgallic acid (compound I), an aglycone of bergenin. The bacterium seemed to utilize the sugar moiety of bergenin preferentially as carbon and energy sources, since the rate of further transformation of compound I by the bacterium was slow. In replacement culture with compound I, gallic acid was detected as one of the metabolites. A possible pathway for microbial degradation of bergenin is proposed.     

Microbial Degradation of a Macrotetrolide Miticide in Soil

Macrotetrolide, a miticide consisting of tetranactin, trinactin, and dinactin, was readily biodegradable and hence did not accumulate in soil. [U-¹⁴C]macrotetrolide was rapidly degraded via its constituent hydroxycarboxylic acids to carbon dioxide and water. In culture media, however, the mixture was hydrolyzed to homononactic and nonactic acids by three strains of Bacillus sp. and two of Micrococcus sp. The latter strains were able to hydrolyze 500 μg of the antibiotic per ml within a few days and to grow in the presence of 4,000 μg of the antibiotic per ml. However, they were unable to assimilate the constituent acids which accumulated in the culture medium.     

Mercury-Resistant Bacteria and Petroleum Degradation

The concentration of mercury in water and sediment and in the oil extracted from water and sediment was determined for samples collected in Colgate Creek, located in Baltimore Harbor of the Chesapeake Bay. The concentration of mercury in the oil was 4,000 times higher than in sediment and 300,000 times higher than in water samples. The mercury-resistant bacterial populations of the samples studied have been shown to degrade oil, suggesting these bacteria to be a significant factor in the degradation of oil in Colgate Creek.     

Microbial Degradation of 3,4-Dichloroaniline Sorbed by Activated Carbon

The availability of 3,4-dichloroaniline (DCA) sorbed by activated carbon to degradative microorganisms was studied. A Paracoccus denitrificansstrain capable of growing on medium with DCA as the sole source of energy, carbon, and nitrogen was used in the experiment. The high sorption capacity of all the carbons studied (powdered RS and SKT-6A and granular AG-3) in relation to DCA (350 to 360, 480 to 520, and 540 to 580 mg/g, respectively) was demonstrated. The sorptive capacity correlated positively with the specific surface area and the total volume of the sorbent micropores. The bulk of the DCA was reversibly sorbed and amenable to microbial degradation; however, the degradation rates significantly differed. When RS, SKT, and Agrosorb preliminarily saturated with DCA were incubated in a culture of P. denitrificans, the bulk of the reversibly sorbed DCA was decomposed (in the absence of the other carbon sources) in 2, 5, and 10 weeks, respectively, after which the process slowed down. At the end of the experiment (29 weeks), 81 to 87% of the DCA underwent full mineralization, which was accompanied by the release of chlorine ions. A small fraction of the xenobiotic (0.8 to 1.9%) remained a reversibly sorbed fraction (extractable with acetone) and 12 to 17% of the initial DCA seemed to have been chemically transformed and bound by carbon. The studied carbons may be used in biological decontamination of chloroaniline-polluted soils to decrease the toxic effect of chloroanilines on microorganisms.     

Microbial Degradation of Polyethylene Glycols

Three bacterial strains have been isolated that differ in their ability to degrade polyethylene glycols (PEGs). Strains R and O showed a marked preference for growth on the low and high molecular weight PEGs, respectively, while strain Z utilized mono-ethylene glycol only. The partial degradation of PEG 200 by strains R and O was studied in some detail and the results suggested that those components of the mixture that were not utilized were converted into acidic derivatives which accumulated in the medium.     

Microbial Degradation of High-Molecular-Weight Alkanes

Measurements of biological O(2) demand showed that normal alkanes containing up to 44 carbon atoms were metabolized by microorganisms.     

Microbial Degradation of Polyethylene Glycols

Mono-, di-, tri-, and tetraethylene glycols and polyethylene glycols (PEG) with molecular weight up to 20,000 were degraded by soil microorganisms. A strain of Pseudomonas aeruginosa able to use a PEG of average molecular weight 20,000 was isolated from soil. Washed cells oxidized mono and tetraethylene glycols, but O₂ consumption was not detectable when such cells were incubated for short periods with PEG 20,000. However, the bacteria excreted an enzyme which converted low- and high-molecular-weight PEG to a product utilized by washed P. aeruginosa cells. Gas chromatography of the supernatant of a culture grown on PEG 20,000 revealed the presence of a compound co-chromatographing with diethylene glycol. A metabolite formed from PEG 20,000 by the extracellular enzyme preparation was identified as ethylene glycol by combined gas chromatography-mass spectrometry.     

Methods of Staining Plant Tissues for Differentiating the Natural Plant Oils from Petroleum Spray Oils

Petroleum, spray oils in sections of plant tissue have been distinguished from the plant oils by staining the fresh sections in the following dye solution: To a saturated aqueous solution of Nile blue sulfate, 0.5% sulfuric acid is added and the mixture is boiled under a reflux condenser for 4 or 5 hours. It should be as nearly alkaline as possible without a change of color. A solution of 50% alcohol and 50% acetone is then saturated with oil red O. One part of the Nile blue sulfate solution is then added to two parts of the oil red O solution. Allow to settle over night and filter. Stain several hours. Rinse in water and mount in glycerin jelly. A short discussion of the merits of this method and the differentiation of the spray oils by means of indophenol blue are also given.     

Degradation of Nucleic Acids and Related Compounds by Microbial Enzymes

The culture filtrate of a strain of Bacillus subtilis decomposed ribonucleic acid into 5′-nucleotides and into other intermediates which released orthophosphate by an arsenate-resistant phosphatase. Under the best conditions examined in these experiments, about 50 per cent of ribonucleic acid was converted into 5′-nucleotides.

The culture filtrate of a strain of Bacillus brevis showed slight activities of ribonuclease and/or phosphodiesterase which produced 5′-nucleotides from ribonucleic acid, but showed predominant activity of 5′-adenylic acid degrading phosphatase.     

瘤胃微生物对纤维素的降解及其应用

瘤胃微生物主要包括细菌、真菌和原生动物。其中,瘤胃细菌和瘤胃真菌能分泌纤维素酶,对纤维素有较强的降解能力,主要介绍了瘤胃微生物对纤维素的降解作用及其广阔的应用前景。     

Anaerobic Degradation of Hexadecan-2-one by a Microbial Enrichment Culture under Sulfate-Reducing Conditions

A microbial enrichment culture from marine sediment was able to grow on hexadecan-2-one as the sole source of carbon and energy under sulfate-reducing conditions. Oxidation of the ketone involved carboxylation reactions and was coupled to sulfide production. This enrichment culture also grew on 6,10,14-trimethylpentadecan-2-one.     

Microbial Degradation of Natural Rubber Vulcanizates

An actinomycete, Nocardia sp. strain 835A, grows well on unvulcanized natural rubber and synthetic isoprene rubber, but not on other types of synthetic rubber. Not only unvulcanized but also various kinds of vulcanized natural rubber products were more or less utilized by the organism as the sole source of carbon and energy. The thin film from a latex glove was rapidly degraded, and the weight loss reached 75% after a 2-week cultivation period. Oligomers with molecular weights from 10⁴ to 10³ were accumulated during microbial growth on the latex glove. The partially purified oligomers were examined by infrared and ¹H nuclear magnetic resonance and ¹³C nuclear magnetic resonance spectroscopy, and the spectra were those expected of cis-1, 4-polyisoprene with the structure, OHC—CH₂—[—CH₂—C(—CH₃)=CH —CH₂—]_n—CH₂—C(=O)— CH₃, with average values of n of about 114 and 19 for the two oligomers.