16S rDNA sequence analysis of culturable marine biofilm forming bacteria from a ship's hull

Marine bacteria from the hull of a ship in the form of biofilms or microfouling were isolated, cultured, and identified by phylogenetic analysis using 16S rDNA sequences. With an average length of 946 bp, all the 16 sequences were classified using the Ribosomal database project (RDP) and were submitted to the National Center for Biotechnology Information. Phylogenetic analysis using 16S rDNA sequences indicated that the 16 strains belonged to the Firmicutes (IK-MB6 Exiguobacterium aurantiacum, IK-MB7 Exiguobacterium arabatum, IK-MB8 Exiguobacterium arabatum, IK-MB9 Jeotgalibacillus alimentarius, IK-MB10 Bacillus megaterium, IK-MB11 Bacillus pumilus, IK-MB12 Bacillus pumilus, IK-MB13 Bacillus pumilus, IK-MB14 Bacillus megaterium), High GC, Gram-positive bacteria (IK-MB2 Micrococcus luteus, IK-MB5 Micrococcus luteus, IK-MB16 Arthrobacter mysorens), G-Proteobacteria (IK-MB3 Halomonas aquamarina, IK-MB15 Halotalea alkalilenta), CFB group bacteria (IK-MB1 Myroides odoratimimus), and Enterobacteria (IK-MB4 Proteus mirabilis). Among the 16 strains, representatives of the Firmicutes were dominant (56.25%) compared to the high GC, Gram-positive bacteria (18.75%), G-Proteobacteria (12.5%), CFB group bacteria (6.25%), and Enterobacteria (6.25%). Analysis revealed that majority of marine species found in marine biofilm are of anthropogenic origin.     

Diversity of endophytic bacteria in ginseng and their potential for plant growth promotion

Endophytic bacteria have been found in virtually every plant studied, where they colonize the internal tissues of their host plant and can form a range of different beneficial relationships. The diversity of bacterial endophytes associated with ginseng plants of varying age levels in Korea was investigated. Fifty-one colonies were isolated from the interior of ginseng stems. Although a mixed composition of endophyte communities was recovered from ginseng based on the results of 16S rDNA analysis, bacteria of the genus Bacillus and Staphylococcus dominated in 1-year-old and 4-year-old plants, respectively. Phylogenetic analysis revealed four clusters: Firmicutes, Actinobacteria, α-Proteobacteria, and γ-Proteobacteria, with Firmicutes being predominant. To evaluate the plant growth promoting activities, 18 representative isolates were selected. Amplification of nifH gene confirmed the presence of diazotrophy in only two isolates. Half of the isolates solubilized mineral phosphate. Except four, all the other endophytic isolates produced significant amounts of indole acetic acid in nutrient broth. Iron sequestering siderophore production was detected in seven isolates. Isolates E-I-3 (Bacillus megaterium), E-I-4 (Micrococcus luteus), E-I-8 (B. cereus), and E-I-20 (Lysinibacillus fusiformis) were positive for most of the plant growth promoting traits, indicating their role in growth promotion of ginseng.     

Identification of Diazotrophs in the Culturable Bacterial Community Associated with Roots of <Emphasis Type="Italic">Lasiurus sindicus</Emphasis>, a Perennial Grass of Thar Desert,India

Lasiurus sindicus is a highly nutritive, drought-tolerant, perennial grass that is endemic to the Thar Desert of Rajasthan, India. Analysis of 16S rRNA coding genes of the bacterial isolates enriched in nitrogen-free semisolid medium, from the surface-sterilized roots of L. sindicus, showed predominance of Gram-negative over Gram-positive bacteria. According to comparative sequence analysis of 16S rDNA sequence data, Gram-positive bacteria with low GC content (Staphylococcus warneri and Bacillus sp.) and high GC content (Micrococcus luteus, Microbacterium sp.) were identified. Gram-negative bacteria included Azospirillum sp., Rhizobium sp., Agrobacterium tumefaciens, and Inquilinus limosus (α-proteobacteria); Ralstonia sp., Variovorax paradoxus, and Bordetella petrii (β-proteobacteria); and Pseudomonas pseudoalcaligenes, Stenotrophomonas sp. (γ-proteobacteria). The occurrence of nifH sequences in Azospirillum sp., Rhizobium sp., and P. pseudoalcaligenes showed the possibility of supplying biologically fixed nitrogen by the root-associated diazotrophs to the host plant.     

The Bioremediation Potential of Hydrocarbonoclastic Bacteria Isolated From a Mangrove Contaminated by Petroleum Hydrocarbons on the Cilacap Coast,Indonesia

The main purpose of the study was to isolate strains of bacteria capable of degrading hydrocarbons from contaminated mangroves and to investigate the ability of the isolated bacteria to degrade total petroleum hydrocarbons (TPH) in a microcosm model of an oily sludge. The potential use of these bacteria strains as environmental clean-up agents was tested by culturing them with six different polyaromatic hydrocarbon (PAH) compounds (phenothiazine, fluorene, fluoranthene, dibenzothiophene, phenanthrene, and pyrene). Six viable and culturable bacteria were isolated, and the 16S rDNA sequence for each was amplified using the primers 9F and 1510R. Sequence results were compared using the National Center for Biotechnology Information (NCBI) BLAST program and, combined with phenotypic and phylogenetic data, were used to identify three strains that belonged to the Bacillus genus and were most closely related (98–99%) to Bacillus aquimaris, Bacillus megaterium, and Bacillus pumilus. The other three strains were closely related (98–100%) to Flexibacteraceae bacterium, Halobacilus trueperi, and Rhodobacteraceae bacterium. Two isolates, BA-PZN and BM-PFFP, which were related to Bacillus aquimaris and Bacillus megaterium, respectively, were further characterized and showed great potential for the removal of more complex hydrocarbon compounds in the oily microcosm model.     

Chemotactic attraction between hemocytes of the oyster,Crassostrea virginica,and bacteria

Experiments were conducted to ascertain whether there is chemotactic attraction by Bacillus megaterium and Micrococcus varians, both Gram-positive species, and Escherichia coli and Vibrio parahaemolyticus, both Gram-negative species, for hemocytes of the American oyster, Crassostrea virginica. It was ascertained quantitatively that oyster hemocytes are attracted to live E. coli, B. megaterium, and M. varians but not to heat-killed bacteria. Furthermore, oyster cells are not attracted to either live or heat-killed V. parahaemolyticus. It is concluded that the chemoattractant is some molecule emitted by living vegetative cells of certain Gram-positive as well as Gramnegative bacteria.     

Effects of four Bacillus spp. of soil origin on the Colorado potato beetle Leptinotarsa decemlineata (Say)

Four species of Bacillus were isolated from soil in an effort to find safe, effective and alternative biological control agents against plant pests. These bacteria were identified as Bacillus pumilus, Bacillus sphaericus, Bacillus megaterium and Bacillus cereus on the basis of fatty acid methyl ester analysis and carbon utilization profiles by using Microbial Identification and Biolog Microplate Systems. Laboratory experiments carried out to determine the insecticidal activities of these isolates showed that B. pumilus caused 95.7 and 26.7% mortality and B. sphaericus caused 74.5 and 23.3% mortality of Leptinotarsa decemlineata larvae and adults, respectively. B. cereus and B. megaterium showed 51.1 and 29.7%, respectively, of L. decemlineata larvae. This study presents at least two Turkish isolates from the genus Bacillus showing high insecticidal activity against L. decemlineata.     

Culturable Bacteria Present in the Fluid of the Hooded-Pitcher Plant <Emphasis Type="Italic">Sarracenia Minor</Emphasis> Based on 16S rDNA Gene Sequence Data

The culturable microbial community within the pitcher fluid of 93 Sarracenia minor carnivorous plants was examined over a 2-year study. Many aspects of the plant/bacterial/insect interaction within the pitcher fluid are minimally understood because the bacterial taxa present in these pitchers have not been identified. Thirteen isolates were characterized by 16S rDNA sequencing and subsequent phylogenetic analysis. The Proteobacteria were the most abundant taxa and included representatives from Serratia, Achromobacter, and Pantoea. The Actinobacteria Micrococcus was also abundant while Bacillus, Lactococcus, Chryseobacterium, and Rhodococcus were infrequently encountered. Several isolates conformed to species identifiers (>98% rDNA gene sequence similarity) including Serratia marcescens (isolates found in 27.5% of pitchers), Achromobacter xylosoxidans (37.6%), Micrococcus luteus (40.9%), Bacillus cereus (isolates found in 10.2%), Bacillus thuringiensis (5.4%), Lactococcus lactis (17.2%), and Rhodococcus equi (2.2%). Species–area curves suggest that sampling efforts were sufficient to recover a representative culturable bacterial community. The bacteria present represent a diverse community probably as a result of introduction by insect vectors, but the ecological significance remains under explored.     

Characterization of halophilic bacteria from environmental samples from the brackish water of Pulicat Lake, India

Culture dependent phenotypic characterization and 16S rDNA based phylogenetic analyses were applied to study the aerobic halophilic bacterial population present in the Pulicat brackish-water Lake of India. Five different media were employed for isolation of bacteria. A total of 198 morphotypes were recovered, purified and screened for salt tolerance in nutrient agar medium amended with 5–25% NaCl. Based on 16S rDNA restriction fragment length polymorphism analysis with three restriction endonucleases, 51 isolates tolerant to 5% or more NaCl were grouped into 29 clusters. Phylogenetic analysis using 16S rRNA gene sequences revealed that 29 strains could further be allocated into two clades: 19 to Firmicutes and 10 to γ-Proteobacteria. Firmicutes included low G+C Gram-positive bacteria related to family Bacillaceae, which included five genera Bacillus, Virgibacillus, Rummelibacillus, Alkalibacillus and Halobacillus. Another genera included in Firmicutes was Salimicrobium halophilum. In the γ-Proteobacteria group, all the isolates belonged to one genus Halomonas, represented by six different species Halomonas salina, H. shengliensis, H. salifodinae, H. pacifica, H. aquamarina and H. halophila. Most of the isolates exhibited cellulase, xylanase, amylase and protease activities.     

Mercury-Resistant Bacteria from Permafrost Sediments and Prospects for their Use in Comparative Studies of Mercury Resistance Determinants

Mercury-resistant bacteria were isolated from permafrost sediments of Kolyma lowland and Canada existing over five thousand to two million years. Their content was shown to vary within the range 0.001–2.9% and to depend on the amount of mercury in sampling sites (coefficient of correlation 0.75). A collection of mercury-resistant bacterial strains was created. In this collection, various representatives of both Gram-positive bacteria (Bacillus, Exiguobacterium, Micrococcus, Arthrobacter) and Gram-negative bacteria (Pseudomonas, Acinetobacter, Plesiomonas, Myxobacteriales) were identified. Most resistant bacteria were found to contain determinants homologous to mer-operons of contemporary bacteria. The isolated strains of paleobacteria are proposed to be used for a comparative structural study of contemporary and ancient plasmids and transposons carrying mercury resistance determinants.     

Molecular phylogenetic diversity of Bacillus community and its temporal–spatial distribution during the swine manure of composting

In order to obtain the diversity and temporal–spatial distribution of Bacillus community during the swine manure composting, we utilized traditional culture methods and the modern molecular biology techniques of polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) and –denaturing gradient gel electrophoresis (PCR-DGGE). Bacillus species were firstly isolated from the composting. Based on temperature changes, the temporal–spatial characteristics of total culturable Bacillus were remarkable that the number of the culturable Bacillus detected at the high-temperature stage was the highest in each layer of the pile and that detected in the middle layer was the lowest at each stage of composting respectively. The diversity of cultivated Bacillus species isolated from different composting stages was low. A total of 540 isolates were classified by the RFLP method and partial 16S rDNA sequences. They affiliated to eight species including Bacillus subtilis, Bacillus cereus, Bacillus thuringiensis, Bacillus anthracis, Bacillus megaterium, Bacillus licheniformis, Bacillus pumilus, and Bacillus circulans. The predominant species was B. subtilis, and the diversity of culturable Bacillus isolated in the middle-level samples at temperature rising and cooling stages was the highest. The DGGE profile and clone library analysis revealed that the temporal–spatial distribution of Bacillus community was not obvious, species belonging to the Bacillus were dominant (67%) with unculturable bacteria and B. cereus was the second major culturable Bacillus species. This study indicated that a combination of culture and culture-independent approaches could be very useful for monitoring the diversity and temporal–spatial distribution of Bacillus community during the composting process.     

Antibacterial activity of different degree of hydrolysis of palm kernel expeller peptides against spore-forming and non-spore-forming bacteria

Aims: The goal of this study was to determine inhibitory effect of palm kernel expeller (PKE) peptides of different degree of hydrolysis (DH %) against spore‐forming bacteria Bacillus cereus, Bacillus circulans, Bacillus coagulans, Bacillus licheniformis, Bacillus megaterium, Bacillus pumilus, Bacillus stearothermophillus, Bacillus subtilis, Bacillus thuringiensis, Clostridium perfringens; and non‐spore‐forming bacteria Escherichia coli, Lisinibacillus sphaericus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium and Staphylococcus aureus. Methods and Results: A range of DH % (50–100) of PKE peptides was prepared using alcalase, and hydrolysis conditions were determined using response surface methodology (RSM). The influence of pH (6·5–10·5), temperature (35–65°C), enzyme/substrate ratio (1–5%) and substrate concentration (1–2%) were studied on the response of the DH. The antibacterial activity of different DH % of PKE peptides was tested by using disc diffusion assay and micro‐broth dilution assay. According to the minimum inhibitory concentration (MIC) test on each of the PKE peptides of different DH %, the 70 DH % PKE peptide showed greater inhibitory effect compared to the 100 DH % PKE peptide against B. cereus, B. coagulans, B. megaterium, B. pumilus, B. stearothermophillus, B. subtilis, B. thuringiensis, Cl. perfringens, Lisinibacillus sphaericus and L. monocytogenes. Conclusions: The 70 DH % PKE peptides exhibited greatest overall antibacterial effect of the various peptides of PKE evaluated. Further research is needed to determine the mode of action of PKE peptides. Significance and Impact of the Study: Palm kernel expeller peptides, a natural plant product, effectively inhibited the growth of spore‐forming and non‐spore‐forming Gram‐positive bacteria. Potentially, PKE peptides could be used in food preservation and developed as antibacterial agent in the pharmaceutical industry.     

Isolation,identification, and algicidal activity of marine bacteria against <Emphasis Type="Italic">Cochlodinium polykrikoides</Emphasis>

The aim of this study was to isolate and identify algicidal bacteria against the dinoflagellate Cochlodinium polykrikoides, and to determine the algicidal activity and algicidal range. During the declining period of C. polykrikoides blooms, seven algicidal bacteria were isolated. The algicidal bacteria against C. polykrikoides were enumerated using the most probable number (MPN) method. The number of algicidal bacteria was high (3.7 × 10³ mL⁻¹). Algicidal bacteria were identified on the basis of biochemical and chemotaxonomic characteristics, and analysis of 16S rDNA sequences. Seven algicidal bacteria isolated in this study belonged to the genera Bacillus, Dietzia, Janibacter, and Micrococcus. The most algicidal bacterium, designated Micrococcus luteus SY-13, is assumed to produce secondary metabolites. When 5% culture filtrate of this strain was applied to C. polykrikoides cultures, over 90% of C. polykrikoides cells were destroyed within 6 h. M. luteus SY-13 showed significant algicidal activities against C. polykrikoides and a wide algicidal range against various harmful algal bloom (HAB) species. Taken together, our results suggest that M. luteus SY-13 could be a candidate for controlling HABs.     

Unique antimicrobial spectrum of ophiobolin K produced by Aspergillus ustus

A co-cultivation study of two fungal strains showed that Aspergillus ustus could inhibit Aspergillus repens growth. The bioactive compound responsible for the observed activity was purified and identified as a sesterterpene, ophiobolin K. Ophiobolin K exhibited marked inhibition against both fungi and bacteria, especially A. repens, A. glaucus and gram-positive bacteria including Bacillus subtilis, Staphylococcus aureus, and Micrococcus luteus.     

多脂长喙壳菌次生代谢产物的抑菌活性研究

植物病原真菌是生态系统的重要组成部分,能够代谢产生多种生物活性物质。用纸片法检测多脂长喙壳菌(Ceratocystis adiposa)发酵提取物对13种致病细菌的抑菌活性,并对潜在抗菌活性化合物的热、酸碱和光稳定性进行检测,同时应用OSMAC策略寻找多脂长喙壳菌产抗菌化合物的最佳培养条件。结果表明:多脂长喙壳菌提取物对革兰阳性菌——蜡样芽胞杆菌(Bacillus cereus)、缓慢芽胞杆菌(Bacillus lentus)、藤黄微球菌(Micrococcus luteus)具有抗菌活性,MIC分别为6.25、3.125和1.562 5 mg/m L,抗菌化合物具有较好的耐热、耐酸碱和耐辐射性,培养基种类、培养时间和接种量会影响多脂长喙壳菌抗菌化合物的产生,为多脂长喙壳菌抗菌化合物的开发利用提供参考。     

土壤中可编码乌头酸异构酶的芽胞杆菌菌株筛选及鉴定

【目的】以芽胞杆菌(Bacillus)为筛选对象,分离土壤中可编码乌头酸异构酶(aconitate isomerase,AI)的革兰氏阳性(Gram positive,G+)菌株,以丰富对AI分布的科学认识,为其生物学功能研究奠定理论与材料基础。【方法】采用土样高温预处理法、含反式乌头酸(trans-aconitic acid,TAA)唯一碳源的ACO固体平板培养法,结合16S rDNA基因序列同源性分析,筛选能够编码AI的芽胞杆菌目的菌株。【结果】共分离得到22株能够利用TAA碳源的细菌菌株,成功鉴定了其中的16株,分别为巨大芽胞杆菌(Bacillus megaterium) 2株,阿氏芽胞杆菌(Bacillus aryabhattai) 7株,短小芽胞杆菌(Bacillus pumilus) 1株,未鉴定到种的芽胞杆菌(Bacillus sp.) 6株;且它们所含AI编码基因与已知AI基因在序列上存在差异。【结论】首次证明可编码AI的芽胞杆菌细菌种类具有多样性,暗示G+细菌广泛编码AI的可能性,更新了AI几乎只在G–细菌中分布的观点,为后续深入挖掘AI基因及其生物学功能研究提供更多可用微生物资源。     

Dominance of endospore-forming bacteria on a Rotating Activated Bacillus Contactor biofilm for advanced wastewater treatment

The bacterial diversity inherent to the biofilm community structure of a modified rotating biological contactor wastewater treatment process, referred to as the Rotating Activated Bacillus Contactor (RABC) process, was characterized in this study, via both culture-dependent and culture-independent methods. On the basis of culture-dependent methods, Bacillus sp. were found to exist in large numbers on the biofilm (6.5% of the heterotrophic bacteria) and the microbial composition of the biofilms was quite simple. Only three phyla were identified-namely, the Proteobacteria, the Actinobacteria (High G+C Gram-positive bacteria), and the Firmicutes (Low G+C Gram-positive bacteria). The culture-independent partial 16S rDNA sequence analysis revealed a considerably more diverse microbial composition within the biofilms. A total of eight phyla were recovered in this case, three of which were major groups: the Firmicutes (43.9%), the Proteobacteria (28.6%), and the Bacteroidetes (17.6%). The remaining five phyla were minor groups: the Planctomycetes (4.4%), the Chlorobi (2.2%), the Actinobacteria (1.1%), the Nitrospirae (1.1%), and the Verrucomicrobia (1.1%). The two most abundant genera detected were the endospore-forming bacteria (31.8%), Clostridium and Bacillus, both of which are members of the Firmicutes phylum. This finding indicates that these endospore-forming bacteria successfully colonized and dominated the RABC process biofilms. Many of the colonies or clones recovered from the biofilms evidenced significantly high homology in the 16S rDNA sequences of bacteria stored in databases associated with advanced wastewater treatment capabilities, including nitrification and denitrification, phosphorus accumulation, the removal of volatile odors, and the removal of chlorohydrocarbons or heavy metals. The microbial community structures observed in the biofilms were found to correlate nicely with the enhanced performance of advanced wastewater treatment protocols.     

Diversity of Alkaliphilic and Alkalitolerant Bacteria Cultivated from Decomposing Reed Rhizomes in a Hungarian Soda Lake

Bacterial communities associated with decomposing rhizomes of Phragmites australis were investigated in Lake Fertő (Neusiedlersee, Hungary). Alkaliphilic and alkalitolerant strains were isolated on cellulose-containing alkaline medium spread with dilutions of scrapings taken from the surface of the decaying plant material. Fifty-one strains were grouped by numerical analysis based on physiological tests and BIOLOG sole carbon source utilization data. The strains identified by 16S rDNA sequence comparisons included members of low G+C Gram positives (Marinibacillus marinus, Bacillus cereus, and Exiguobacterium aurantiacum), high G+C Gram positives (Nesterenkonia halobia and Dietzia natronolimnea), α-proteobacteria (Pannonibacter phragmitetus), and γ-proteobacteria (Pseudomonas pseudoalcaligenes and Halomonas venusta). Most of the strains were characterized by aerobic chemoorganotrophic respiratory metabolism and utilized several different carbon sources, although no direct cellulolytic activity was observed. Results of the pH and salt tolerance tests revealed optimuma in most cases at pH 11 and at the presence of 2.5–5% NaCl. These bacteria probably occupy niches in the aerobic, alkaline, water-influenced environments on the decomposing reed surfaces.     

Rumen Bacterial Community Transition During Adaptation to High-grain Diet

Transitional changes of the ruminal bacterial community structure in cows during the switch from roughage to high-grain diet were monitored by PCR amplification and sequencing of 16S rDNA clone libraries. In total, one hundred fifty 16S rDNA sequences of almost full-length (1.4 kb) were analysed from three libraries prepared from the rumen fluid on day 0, 3, and 28 of switch to high-grain diet. In the first library (day 0, hay diet) of 51clones, 90.2% of sequences were belonging to the low G+C Gram-positive bacteria (LGCGPB) phylum, with the minor inclusion of theCytophaga-Flavobacter-Bacteroides (CFB;3.9%), Proteobacteria (3.9%) and high G+C Gram-positive bacteria (HGCGPB;2.0%) phyla-related sequences. Six LGCGPB sequences were clustered with the well-known cellulolytics of the rumen, Ruminococcus flavefaciens and R. albus. In the second library (day 3 of high-grain diet) of 58 clones, the LGCGPB-related sequences still dominated (72.4%), albeit being represented by other species than in the first library. In particular, this library was enriched by representatives of Selenomonas-Succiniclasticum-Megasphaera group IX (17.2%), lactobacilli- (6.9%) and Butyrivibrio fibrisolvens lineage 3-related (8.6%) sequences. Other phyla were represented by CFB (22.4%) and HGCGPB (3.4%). In the third library (day 28 of high-grain diet) of 41 clones, 95% of sequences fell into the LGCGPB phylum. About half of them (46%) were clustered within theSelenomonas-Succiniclasticum-Megasphaera group in Clostridium cluster IX. No HGCGPB-related sequences were detected and CFB was represented by only a single clone. No Streptococcus bovis -related sequences were detected in any of the three clone libraries.     

Synthesis and in vitro microbiological evaluation of novel diethyl 6,6′-(1,4-phenylene)bis(4-aryl-2-oxo-cyclohex-3-enecarboxylates)

Novel bis cyclohexenone ester derivatives 14–19 were synthesized and characterized by their spectral data. In vitro microbiological evaluations were carried out for all the novel compounds 14–19 against clinically isolated bacterial and fungal strains. Compounds 15, 16, 18 against Staphylococcus aureus, 14, 15 against β-Haemolytic streptococcus, 15, 19 against Micrococcus luteus, 17, 18 against Salmonella typhii, 14, 17 against Shigella flexneri, 15 against Escherichia coli, 16 against Pseudomonas aeruginosa, 15, 18, 19 against Klebsiella pneumonia exhibited potent antibacterial activity at an minimum inhibitory concentration (MIC) value of 6.25 μg/ml, whereas compound 16 against Aspergillus flavus, 17 against A. niger, 16, 18 against Mucor indicus, 15, 17–19 against Microsporum gypseum revealed excellent antifungal activity at an MIC value of 6.25 μg/ml.     

Characterization of corrosive bacterial consortia isolated from petroleum-product-transporting pipelines

Microbiologically influenced corrosion is a problem commonly encountered in facilities in the oil and gas industries. The present study describes bacterial enumeration and identification in diesel and naphtha pipelines located in the northwest and southwest region in India, using traditional cultivation technique and 16S rDNA gene sequencing. Phylogenetic analysis of 16S rRNA sequences of the isolates was carried out, and the samples obtained from the diesel and naphtha-transporting pipelines showed the occurrence of 11 bacterial species namely Serratia marcescens ACE2, Bacillus subtilis AR12, Bacillus cereus ACE4, Pseudomonas aeruginosa AI1, Klebsiella oxytoca ACP, Pseudomonas stutzeri AP2, Bacillus litoralis AN1, Bacillus sp., Bacillus pumilus AR2, Bacillus carboniphilus AR3, and Bacillus megaterium AR4. Sulfate-reducing bacteria were not detected in samples from both pipelines. The dominant bacterial species identified in the petroleum pipeline samples were B. cereus and S. marcescens in the diesel and naphtha pipelines, respectively. Therefore, several types of bacteria may be involved in biocorrosion arising from natural biofilms that develop in industrial facilities. In addition, localized (pitting) corrosion of the pipeline steel in the presence of the consortia was observed by scanning electron microscopy analysis. The potential role of each species in biofilm formation and steel corrosion is discussed.