Gordonia sp. LAM0048的分离鉴定及其降解正十六烷的研究

以正十六烷为唯一碳源,从长期受石油污染的土壤中筛选到一株高效降解正十六烷的菌株LAM0048。通过形态学观察、生理生化试验、细胞化学组分分析、16S rRNA基因序列分析、细胞脂肪酸和极性脂试验,确定其属于棒杆菌亚目(Corynebacterineae)、诺卡菌科(Nocardiaceae)、戈登氏属(Gordonia),且可能为戈登氏属的一株新种。采用单因素实验对菌株LAM0048在无机盐培养基中降解正十六烷的降解率进行初步探讨,发现该菌株能在以正十六烷为唯一碳源的培养基中生长,菌株LAM0048能够在36 h内完全降解0.05%(V/V)的正十六烷,当烷烃浓度达到1.0%(V/V)时,降解率达46.4%。结果表明LAM0048是一株具有耐受高浓度烷烃的石油降解菌,在石油污染环境的微生物修复中具有一定的应用潜力。     

Isolation and taxonomic study of a new canthaxanthin-containing bacterium, Gordonia jacobaea MV-1 sp. nov.

This article describes the isolation and taxonomic study of a coryneform isolate of a new Gordonia species (G. jacobaea), strain MV-1, which accumulates several carotenoids, including the ketocarotenoid trans-canthaxanthin. Identification of this new isolate by morphobiochemical methods did not allow unambiguous taxon assignment, but sequencing of the 16S rRNA gene clearly pointed to the genus Gordonia, Gordonia sputi being the closest fit. Differences in certain transversions/transitions in otherwise very well-conserved sequences of the described Gordonia species supported the proposal of this new taxon. The fact that both the best growth and best pigmentation were obtained with glucose, an inexpensive carbon source and at an industrially suitable temperature, suggests that this new bacterial strain may have good potential for the industrial production of canthaxanthin.     

Characterization of cadmium removal by Rhodotorula sp. Y11

Experiments were conducted studying the removal of Cd²⁺ from water via biosorption using Rhodotorula sp. Y11. The effects of temperature and initial pH of the solution on biosorption were studied. Caustic and heat treatments showed different influences on the biosorption capacity, and the highest metal uptake value (19.38 mg g⁻¹) was obtained by boiling treated yeast cells. The presence of competing cations, such as Ag⁺, Cu²⁺, and Mg²⁺, except Na⁺ ions, significantly interfered with the metal uptake. Results indicate that the Langmuir model gave a better fit to the experimental data than the Freundlich equation. The q ₁₀ value was 11.38 mg g⁻¹ for Cd²⁺ uptake by Y11. Chemical modifications of the biomass demonstrated that carboxyl and amide groups play an important role in Cd²⁺ biosorption.     

三株降解芘的戈登氏菌鉴定及其降解能力

从沈抚灌区多环芳烃污染土壤中筛选出的芘降解菌D44、D82S和D82Q,经形态观察、生理生化试验和16S rDNA序列分析确定均为戈登氏菌属(Gordonia sp.).3株菌的最适生长pH值均为7,当pH值低于5或高于9时,生长均受到明显抑制.降解试验表明,3株菌能以芘、苯并芘、蒽、萘、菲和荧蒽为唯一碳源和能源生长.经过7 d的培养,3株菌对初始浓度为100 mg.L-1的芘的降解率均在65%以上,对初始浓度为50 mg.L-1的苯并芘的降解率分别为79.6%、91.3%和62.8%.通过PCR检测发现D82Q和D82S含有烷烃单加氧酶基因alkB.     

Gordonia sinesedis sp. nov., a novel soil isolate

The taxonomic position of an actinomycete isolated from soil was evaluated using a polyphasic approach. The organism, strain J72, was found to have chemical and morphological properties consistent with its assignment to the genus Gordonia. A nearly complete 16S rDNA sequence of the strain was determined by direct sequencing of the amplified gene. The tested strain formed a distinct phylogenetic line within the evolutionary radiation occupied by the genus Gordonia and was most closely related to G. polyisoprenivorans DSM 44302^T. The phenotypic profile of strain 372 readily distinguishes it from representatives of the validly described species of Gordonia. The combined genotypic and phenotypic data show that strain J72 merits recognition as a new species of Gordonia. The name proposed for the new species is Gordonia sinesedis; the type strain is J72^T (= DSM 44455^T = NCIMB 13802^T). This revised version was published online in June 2006 with corrections to the Cover Date.     

Isolation and process parameter optimization of Aspergillus sp. for removal of chromium from tannery effluent

Five morphologically different fungi were isolated from leather tanning effluent in which Aspergillus sp. and Hirsutella sp. had higher potential to remove chromium. The potential of Aspergillus sp. for removal of chromium was evaluated in shake flask culture in different pH, temperature, inoculums size, carbon and nitrogen source. The maximum chromium was removed at pH 6, temperature 30 degrees C, sodium acetate (0.2%) and yeast extract (0.1%). Aspergillus sp. was applied in 2l bioreactor for removal of chromium, and it was observed that 70% chromium was removed after 3 days.     

Gordonia lacunae sp. nov., isolated from an estuary

An actinomycete, strain BS2^T, was isolated from a sand sample collected from an estuary in Plettenberg Bay, Western Cape Province, South Africa. Based on 16S rRNA gene sequence similarities and chemotaxonomy, strain BS2^T was identified as a member of the genus Gordonia. It exhibited weak antibiosis against Mycobacterium aurum A+ and Mycobacterium smegmatis LR222. Phenotypic and phylogenetic results allowed for the differentiation of strain BS2^T from other species within the genus Gordonia. DNA–DNA hybridization further differentiated strain BS2^T from its nearest phylogenetic neighbour, Gordonia terrae NRRL B-16283^T (57.5±4.4% DNA relatedness). Strain BS2^T is therefore a novel species within the genus Gordonia, for which the name Gordonia lacunae is proposed, with the type strain being BS2^T (=DSM 45085^T=NRRL B-24551^T).     

Isolation of the crude oil degrading marine Acinetobacter sp. E11

The Acinetobacter sp. E11, isolated from Port Dickson Beach, Malaysia, was able to grow in media containing crude oil as the sole carbon and energy source. Substrate specificity studies showed that the bacterium exhibited substrate preference as growth was observed only in media containing aliphatic hydrocarbons, while aromatic and cyclic hydrocarbons inhibited growth. With the aliphatic hydrocarbons, growth was seen only in the long-chain alkanes tested (pentadecane, dodecane and hexadecane). No growth was recorded in the short-chain alkanes (pentane, hexane and heptane) tested. With complex hydrocarbons, only crude oil and 4T SHELL engine oil supported growth. No growth was observed in kerosene and PETRONAS gasoline. The isolate could grow in up to 10% and 20% [v/v] of the crude oil and alkanes tested, respectively. Among the long-chain alkanes tested, hexadecane was the most preferred, followed by pentadecane and dodecane. Nitrogen and phosphorous supplements were essential for growth and the best growth was achieved with 3% nitrogen/phosphorous additions. Microscopic observation revealed that the bacterium adhered to the hexadecane and crude oil droplets. GC analysis showed that the bacterium was able to degrade more than 60% of the hydrocarbons in the crude oil in 15 days at 37°C compared to the uninoculated media.     

一株可利用甲烷的克雷伯氏菌的分离及其在甲烷检测中的应用

从山西太原水稻田土壤中,分离得到一株能以甲烷为唯一碳源和能源生长的菌株C611。通过生理生化特征及16SrDNA序列分析,该菌株初步鉴定为克雷伯氏菌(Klebsiella sp.)。采用响应面法优化了该菌株利用甲烷的培养条件,得到最佳培养条件为:温度24.4oC、接种量为6.7%、甲烷含量25%。以C611固定化细菌和溶氧响应仪为体系,采用电化学法研究了不同含量甲烷的响应时间以及溶氧变化与甲烷含量的关系。结果表明,菌株C611能利用甲烷,该反应体系对0～10%甲烷气体测定的响应时间小于100s;溶氧消耗量与通入甲烷气体含量呈线性关系,拟合系数(R2)为0.9994。以3%甲烷气体样品进行8次测量,测定平均值为3.09%,RSD为3.48%,相对误差为3%。表明该反应体系重现性良好,为该菌株进一步研究甲烷传感器奠定基础。     

Degradation of Car Engine Base Oil by Rhodococcus sp. NDKK48 and Gordonia sp. NDKY76A

Two microorganisms (NDKK48 and NDKY76A) that degrade long-chain cyclic alkanes (c-alkanes) were isolated from soil samples. Strains NDKK48 and NDKY76A were identified as Rhodococcus sp. and Gordonia sp., respectively. Both strains used not only normal alkane (n-alkane) but also c-alkane as a sole carbon and energy source, and the strains degraded more than 27% of car engine base oil (1% addition).     

Metabolism of butyl benzyl phthalate by Gordonia sp. strain MTCC 4818

The microbial degradative characteristics of butyl benzyl phthalate (BBP) were investigated by the Gordonia sp. strain MTCC 4818 isolated from creosote-contaminated soil. The test organism can utilize a number of phthalate esters as sole sources of carbon and energy, where BBP was totally degraded within 4 days under shake culture conditions. High performance liquid chromatography profile of the metabolites isolated from spent culture indicated the accumulation of two major products apart from phthalic acid (PA), which were characterized by gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy as mono-n-butyl phthalate (MBuP) and monobenzyl phthalate (MBzP). Neither of the metabolites, MBuP, MBzP or PA, supported growth of the test organism, while in resting cell transformation, the monoesters were hydrolyzed to PA to a very minor extent, which was found to be a dead-end product in the degradation process. On the other hand, the test organism grew well on benzyl alcohol and butanol, the hydrolyzed products of BBP. The esterase(s) was found to be inducible in nature and can hydrolyze in vitro the seven different phthalate diesters tested to their corresponding monoesters irrespective of their support to the growth of the test organism.     

Improved biodesulfurization of hydrodesulfurized diesel oil using Rhodococcus erythropolis and Gordonia sp.

Substituted benzothiophenes (BTs) and dibenzothiophenes (DBTs) remain in diesel oil following conventional desulfurization by hydrodesulfurization. A mixture of washed cells (13.6 g dry cell wt l⁻¹) of Rhodococcus erythropolis DS-3 and Gordonia sp. C-6 were employed to desulfurize hydrodesulfurized diesel oil; its sulfur content was reduced from 1.26 g l⁻¹ to 180 mg l⁻¹, approx 86% (w/w) of the total sulfur was removed from diesel oil after three cycles of biodesulfurization. The average desulfurization rate was 0.22 mg sulfur (g dry cell wt)⁻¹ h⁻¹. A bacterial mixture is therefore efficient for the practical biodesulfurization of diesel oil.     

Degradation of car engine base oil by Rhodococcus sp. NDKK48 and Gordonia sp. NDKY76A

Two microorganisms (NDKK48 and NDKY76A) that degrade long-chain cyclic alkanes (c-alkanes) were isolated from soil samples. Strains NDKK48 and NDKY76A were identified as Rhodococcus sp. and Gordonia sp., respectively. Both strains used not only normal alkane (n-alkane) but also c-alkane as a sole carbon and energy source, and the strains degraded more than 27% of car engine base oil (1% addition).     

Isolation and characterization of Sphingomonas sp. GTIN11 capable of carbazole metabolism in petroleum

A bacterial culture was isolated from a manufactured gas plant (MGP) soil based on its ability to metabolize the nitrogen-containing heterocycle carbazole. The culture was identified as a Sphingomonas sp. and was given the designation GTIN11. A cloned 4.2kb DNA fragment was confirmed to contain genes responsible for carbazole degradation. DNA sequence analysis revealed that the fragment contained five open reading frames (ORFs) with the deduced amino acid sequence showing homology to; carbazole terminal dioxygenase (ORF1), 2,3-dihydroxybiphenyl dioxygenase subunits (ORF2 and ORF3), meta-cleavage compound hydrolases (ORF4), and ferrodoxin component of bacterial multicomponent dioxygenases (ORF5). The percent similarity was 61% of these proteins or less to known proteins. The specific activity of Sphingomonas sp. GTIN11 for the degradation of carbazole at 37 degrees C was determined to be 8.0 micromol carbazole degraded/min/g dry cell. This strain is unique in expressing the carbazole degradation trait constitutively. Resting cells of Sphingomonas sp. GTIN11 removed 95% of carbazole and 50% of C1-carbazoles from petroleum in a 16-h treatment time.     

Biodesulfurization of dibenzothiophene by growing cells of Gordonia sp. in batch cultures

A new isolate, identified as Gordonia sp. ZD-7 by 16S rDNA sequence analysis, grew in n-hexadecane containing dibenzothiophene (DBT) which was degraded from 2.8 mM to 0.2 mM within 48 h. Biodesulfurization could be repeatedly performed for more than 190 h, with average desulfurization rates of 5 mmol DBT kg cells (dry wt)⁻¹ h⁻¹.     

Isolation and some properties of newly isolated oxalate-degrading Pandoraea sp. OXJ-11 from soil

AIMS: To isolate and characterize an oxalate-degrading Pandoraea sp. OXJ-11. METHODS AND RESULTS: A new bacterium Pandoraea sp. OXJ-11 was isolated from soil samples, which can grow in the medium with oxalate as the sole carbon and energy source. The isolate OXJ-11 is Gram-negative straight rod. It occurs singly and is motile by means of a double polar flagellum. Catalase is positive and nitrate is not reduced. It grows aerobically and the optimum growth temperature and the optimum pH are at 30 degrees C and pH 6.0, respectively. The polyphasic taxonomic data along with 16S rRNA sequence comparison demonstrate that the isolate OXJ-11 should belong to the genus Pandoraea and represent a new member in this family. CONCLUSIONS: Oxalate could be degraded and the oxalate-degrading enzyme activity was detected when the isolate OXJ-11 grew in the medium with oxalate as carbon source. SIGNIFICANCE AND IMPACT OF THE STUDY: Oxalate-degrading Pandoraea sp. OXJ-11 would be beneficial to the potential application in the control of sclerotinia stem rot in economically important plants caused by fungus Sclerotinia sclerotiorum, and in making plants resistant to the white mold disease by oxalate-degrading enzyme transgene.     

Isolation and characterization of a xanthan-degrading Microbacterium sp. strain XT11 from garden soil

AIMS: Isolation and characterization of the xanthan-degrading Microbacterium sp. XT11. METHODS AND RESULTS: The bacterial isolate XT11, capable of fragmenting xanthan, has been isolated from soil sample. Morphological and biochemical analyses, as well as 16S rRNA gene sequence comparisons, demonstrated that strain XT11 should be grouped in the genus Microbacterium, and represented a new member in this family. Xanthan could be degraded by the xanthan-degrading enzyme released from strain XT11. It has been shown that xantho-oligosaccharides fragmented from xanthan had both elicitor activity and antibacterial effect against Xanthomonas campestris pv. campestris. CONCLUSIONS: The xanthan-degrading enzyme produced by the newly isolated XT11 could fragment xanthan to form oligosaccharides. SIGNIFICANCE AND IMPACT OF THE STUDY: Xanthan-degrading products would be useful for potential application in the control of black rot of cruciferous plants caused by X. campestris pv. campestris and, as an oligosaccharide elicitor, in making these plants resistant to disease.     

Isolation of yeast Kurtzmanomyces sp. I-11, novel producer of mannosylerythritol lipid

Yeast strains were screened for producers of glycolipid-type biosurfactants from soybean oil as a sole carbon source. The structure of the glycolipid (MEL-I-11) produced by strain I-11 was analyzed. The hydrophilic sugar moiety was mannosylerythritol and the fatty acid components were C8:0 (36.4%), C12:0 (11.9%), and C14:2 (25.9%). The MEL-I-11 was identified as 6-O-acetyl-2,3-di-O-alkanoyl-beta-D-mannopyranosyl-(1-->4)-O-meso-erythritol. The strain I-11 was identified as a Kurtzmanomyces species, a novel producer of mannosylerythritol lipid.     

Characterization of Gordonia sp. strain F.5.25.8 capable of dibenzothiophene desulfurization and carbazole utilization

A dibenzothiophene (DBT)-degrading bacterial strain able to utilize carbazole as the only source of nitrogen was identified as Gordonia sp. F.5.25.8 due to its 16S rRNA gene sequence and phenotypic characteristics. Gas chromatography (GC) and GC–mass spectroscopy analyses showed that strain F.5.25.8 transformed DBT into 2-hydroxybiphenyl (2-HBP). This strain was also able to grow using various organic sulfur or nitrogen compounds as the sole sulfur or nitrogen sources. Resting-cell studies indicated that desulfurization occurs either in cell-associated or in cell-free extracts of F.5.25.8. The biological responses of F.5.25.8 to a series of mutagens and environmental agents were also characterized. The results revealed that this strain is highly tolerant to DNA damage and also refractory to induced mutagenesis. Strain F.5.25.8 was also characterized genetically. Results showed that genes involved in desulfurization (dsz) are located in the chromosome, and PCR amplification was observed with primers dszA and dszB designed based on Rhodococcus genes. However, no amplification product was observed with the primer based on dszC.