Genetic Transfer of Auxotrophic Markers in Hydrocarbon-Utilizing Strains of Acinetobacter Lwoffi

Conjugal transfer of chromosomal genes was shown to occur in oil-degrading strains of Acinetobacter lwoffi. High co-inheritance frequencies of auxotrophic makers inconjugation experiments suggested linkage relationships amongst the, trp and arg loci. The significance of gene transfer in Acinetobacter species was discussed

Purification and properties of a neutral protease produced by Lactobacillus brevis

A proteolytic enzyme was produced by a strain of Lactobacillus brevis isolated from an oriental beverage. The enzyme was extracted and purified 50-fold by gel filtration and ion-exchange chromatography. The optimum pH for the enzyme was 7.0, the optimum temperature 35°C and the molecular weight 34,674 Da. Furthermore, the enzyme was stimulated by cations including Ca2+, Mg2+, Na+ and K+ and inhibited by Zn2+ and Co2+ ions. Other inhibitors were EDTA, ascorbic acid and citric acid. The enzyme is probably a neutral metalloprotease

Biodegradation of Produce Water Hydrocarbons by Pure Cultures of Alcaligenes sp.

Biodegradation studies of hydrocarbons in untreated produce water from an oil production facility in Nigeria was undertaken over a period of time using pure cultures of Alkaligenes sp. Isolated from Escravos River where produce water was being discharged as at the time the studies were carried out. Gas chromatography and mass spectrometry were used to monitor the rate of reduction in some petroleum hydrocarbon fractions while the index used to evaluate biodegradation was the decreasing trend in the ratios of nC17/Pristane and nC18/Phytane. Gas chromatographic analysis showed that untreated produced water used for the study had an oil and grease content of 1407mg/L, this includes n-alkanes (608mg/L), Aromatics (13.88mg/L), NSO compounds (12.68mg/L) PAHs(0.833mg/L) and some unidentified greasy components. Upon mechanical treatment, the oil and grease component of produce water was reduced to 44mg/L comprising of n-alkanes (38.40mg/L), Aromatics (2.65mg/L), NSO compounds (1.78mg/L), PAHs (0.0655mg/L) and some unidentified greasy component. A pure culture of Alcaligenes sp. after 40 days of exposure to untreated produced water reduced the oil and grease content to 19.58mg/l comprising of n-Alkanes (16.87mg/l), Total aromatics (1.25mg/l), NSO compounds (0.98mg/l) and PAH (0.0096mg/l). This result indicate that produce water is readily biodegradable and pure cultures of Alcaligenes sp. used for the study were very efficient in the degradation of produced water hydrocarbons especially the recalcitrant PAH component when compared with the conventional mechanical treatment process. [Journal of American Science 2010;6(4):107-113]. (ISSN: 1545-1003)

Induction of Souring and Corrosion by Anaerobic Microbial Activities in Offshore and Nearshore Oil-Producing Facilities in Nigeria

Anaerobic microbiological activities of two oil-producing facilities were determined by monitoring microbial activities in CSB-K medium and MPN counts of SRB in API RP-38 broth medium and APB in ZPRA-5 broth medium. Corrosion measurements were also carried out by weight loss method. Our investigation revealed that microbial activities at the near-shore facility were dominated by both sulfate reduction and methanogenesis with potential for souring and corrosion, while that of offshore was dominated by sulfate reduction, but the potential for souring and corrosion were reduced by frequent application of a combination of biocides by the operators

Souring and Corrosion Potentials of Onshore and Offshore Oil-producing Facilities in the Nigerian Oil-rich Niger Delta

Souring and corrosion potentials of two oil producing facilities were determined by monitoring microbial activities in CSB-K medium and MPN counts of SRB and APB in API RP-38 and ZPRA-5 broth medium, respectively. Corrosion rate measurements were carried out by weight loss method. Our investigation revealed that microbiological activities at the onshore facility were dominated by methanogenesis with zero potential for souring and high potential for corrosion while that of offshore facility were dominated by sulfate reduction with high potential for both souring and corrosion. Biocide treatments were effective against the sulfate-reducing bacteria but not effective against the methanogens associated with corrosion

Biodegradation of selected polycyclic aromatic hydrocarbons by axenic bacterial species belonging to the genera Lysinibacillus and Paenibacillus

The quest for competent degraders of recalcitrant polynuclear aromatic hydrocarbons (PAHs) for use in sustainable bioremediation technology has justified the execution of this work. In this study, three bacterial strains (FB-1, FB-2 and FB-3) were isolated from a former industrial site in Bloomington, Indiana. The catabolic versatility of these obtained strains was evaluated on some selected PAH-naphthalene, anthracene, fluoranthene and pyrene. Using the 16S rRNA sequencing analyses, our strains belonged to the family Firmicutes whereby strain FB-1 was identified as Lysinibacillus sp. FB-1, strain FB-2 as Bacterium FB-2 and strain FB-3 as Lysinibacillus fusiformis FB-3. The biodegradation of the selected PAHs was determined using gas chromatography, and the calculated percentage utilization of the selected PAHs varied between 97 and 4%. We further determined the mean biodegradation rates for fluoranthene when supplemented with molasses. The mean biodegradation rates were between (mg L-1 ) 0.214 ± 0.006 and 0.318 ± 0.002, while MSfluoranthene only ranged from (mg L-1) 0.210 ± 0.056 to 0.437 ± 0.176. However, with ANOVA at 5% (P\0.05) there seemed to be no significant difference in the mea

Microbial community structure of a low sulfate oil producing facility indicate dominance of oil degrading/nitrate reducing bacteria and Methanogens

Analysis of microbial community structure of a low sulfate oil producing facility in Nigeria using 16S rRNA gene sequencing technique revealed dominance of oil degrading and nitrate reducing bacteria and methanogenic archaea in produced waters and oil samples namely, Marinobacter (37%), Azovibrio (21%), Thauera (10–28%), and Methanolobus (22%). On the contrary, the associated oil pipeline samples revealed massive dominance of potentially corrosive Methanolobus (60%) and Methanobacterium (25-27%). Further experimentation shows that the methanogens implicated in oil pipelines are corrosive moderate halophile that utilizes H2/CO2 and methanol as substrates. More emphasis should therefore be on methanogenic archaea as opposed to sulfate reducing bacteria (SRBs) during mitigation plans for microbially induced corrosion (MIC) in a low sulfate oil producing facilit

Properties, environmental fate and biodegradation of carbazole

The last two decades had witnessed extensive investigation on bacterial degradation of carbazole, an N-heterocyclic aromatic hydrocarbon. Specifically, previous studies have reported the primary importance of angular dioxygenation, a novel type of oxygenation reaction, which facilitates mineralization of carbazole to intermediates of the TCA cycle. Proteobacteria and Actinobacteria are the predominant bacterial phyla implicated in this novel mode of dioxygenation, while anthranilic acid and catechol are the signature metabolites. Several studies have elucidated the degradative genes involved, the diversity of the car gene clusters and the unique organization of the car gene clusters in marine carbazole degraders. However, there is paucity of information regarding the environmental fate as well as industrial and medical importance of carbazole and its derivatives. In this review, attempt is made to harness this information to present a comprehensive outlook that not only focuses on carbazole biodegradation pathways, but also on its environmental fate as well as medical and industrial importance of carbazole and its derivatives

Pyrene Biodegradation Potential of an Actinomycete, Microbacterium Esteraromaticum Isolated from Tropical Hydrocarbon-Contaminated Soi

A novel pyrene-degrading actinomycete, phylogenetically identified as Microbacterium esteraromaticum strain SL9 was isolated from a polluted hydrocarbon-contaminated soil in Lagos, Nigeria. Growth of the isolate on pyrene was assayed using total viable counts, pyrene degradation was monitored using gas chromatography (GC-FID) while UV-Vis spectrophotometry was used to detect metabolites of pyrene degradation. The isolate tolerated salt concentration of up to 6%, grew luxuriantly on crude oil and exhibited weak utilization of fluorene, acenaphthene and engine oil. It resisted cefotaxime, ciprofloxacin and amoxicilin, but was susceptible to meropenem, linezolid and vancomycin. It also resisted elevated concentrations of heavy metals such as 1-5 mM lead and nickel. On pyrene, the isolate exhibited growth rate and doubling time of 0.023 h-1 and 1.25 h, respectively. It degraded 55.16 (27.58 mg L-1) and 89.28% (44.64 mg L-1) of pyrene (50 mg L-1) within 12 and 21 days respectively, while the rate of pyrene utilization was 0.09 mg L-1h-1. Catechol dioxygenase assay using UV-Vis spectrophotometry revealed the detection of meta cleavage compound, 2-hydroxymuconic semialdehyde in the crude cell lysate. The results of this study showed the catabolic versatility of Microbacterium species on hydrocarbon substrates and their potential as seeds for bioremediation of environments co-contaminated with polycyclic aromatic hydrocarbons and heavy metals

Kraft lignin degradation by autochtonous streptomyces strains isolated from a tropical lagoon ecosystem

Kraft lignin contributes to the toxicity of the pulping plant effluent and is known to resist microbial treatment.The lignin component must be removed from lignocellulose biomass to enhance the release of fermentable sugars for the production of biofuel and other value-added end products. Lignin-degrading bacteria provide an advantage due to their ease of isolation,wider tolerance of environmental conditions and genetic manipulations compared with their fungal counterparts. There is no documented evidence on the degradation of kraft lignin by bacteria in the tropical estuarine ecological niche in Nigeria. Bacterial growth and assessment of kraft-lignin degradation in submerged fermentation was carried out for a period of 10 days using Streptomyces spp isolated from a tropical lagoon as the inocula. The organisms utilized 23 to 99 % kraft-lignin at the rate of 2.3×10-5 to 9.9×10-5 g.d-1cm-3 with specific growth rates of 0.020 - 0.084 h-1and doubling times of 8.3 - 35.1 h. Maximum values obtained for laccase and peroxidase activities were 9.5x10-2 and 400 μ mol mg -1min -1 respectively. The aim of this study was to obtain evidences for Kraft lignin degradation by indigenous tropical estuarine Streptomyces species from Lagos, Nigeria. The Autochthonous bacterial species of the Lagos lagoon utilize kraft lignin as a sole carbon source and may be good candidates for biotechnological purposes. The outcome of this study has bridged an information gap in the tropical environment and will complement existing global data because the information on the degradation of kraft lignin by marine Streptomyces is not common