Biodeterioration of stone: a review

The alteration and weathering of stone is basically determined by natural and anthropogenic impacts influencing various physical, chemical and biological damage factors at the object site. Whether as direct or catalytically enhancing factor, the biodeterioration of stone is coupled with nearly all environmentally induced degradation processes: the presence of the one makes deterioration by the other all the more effective. The bioreceptivity of stone is described by its structure and chemical composition, while the intensity of the microbial contamination is determined by the referring climatic conditions and the anthropogenic euthrophication of the atmosphere. The microflora improves the nutrient and moisture-restricted growth conditions on building stones by the formation of surface-covering biofilms. Besides the aesthetical impairment caused by the coloured biopatina, the biofouling effect promotes even “abiotic” deterioration processes due to the alteration of the material structure as well as their thermo-hygric properties; in addition, mechanical pressure due to the shrinking and swelling of the colloidal biofilms might cause a further weakening of the mineral lattice. Acidolytic and oxido-reductive biocorrosion processes complete the biodeteriorating attack of stone acting as a preliminary precursor for the latter formation of detrimental crusts. Suitable and reliable methods for the detection of biodeterioration processes are available, but only the interdisciplinary diagnosis and evaluation of the entire decay process of stone allows the formulation of adaequate countermeasure strategies. In case the significance of biodeterioration impacts is proven, the possible effects of the microbial contamination on cleaning procedures, protective treatments as well as biocidal applications has to be considered. This paper will give a comprehensive overview to the biodeterioration of stone and stresses the practical relevance for the conservation.     

Biodeterioration of collagen-based cultural relics: A review

Natural collagen-based cultural relics such as parchment and leather are susceptible to the storage environment, including temperature, relative humidity, pollutants, and microorganisms, resulting in the deterioration of the main components of collagen, keratin, tannins, lipids, oils and tanning regents. Significant changes might occur in the appearance, composition and internal structure, accompanied by the impaired physical properties such as thermal stability, flexibility, and tensile strength. Biodeterioration is one of the main factors affecting the long-term storage of parchment and leather artifacts, particularly in environments with high relative humidity, due to the proliferation and growth of bacteria or fungi. This review focuses on the common microbial communities on the parchment and leather artifacts. The biodeterioration mechanism is discussed, which will shed light onto the future research of collagen-based cultural relics.     

Bacterial communities in a crude oil gathering and transferring system (China)

Bacterial communities in crude oil and oil field production water samples from an oil gathering and transferring system in Changqing Oil field in China were investigated by 16S rRNA denaturing gradient gel electrophoresis (DGGE) analysis followed by gene cloning and sequencing. DGGE profiles showed that bacterial communities are far more rich in the water samples than that in the crude oil samples, and that bacteria related to Ochrobactrum sp. and Stenotrophomonas sp. were detected in all crude oil and oil field water samples. Bacteria related to Burkholderia sp., Brevundimonas sp., and Propionibacterium sp. were detected in the crude oil samples but not in water samples. Bacteria related to Hippea sp., Acidovorax sp., Arcobacter sp., Pseudomonas sp., Thiomicrospira sp., Brevibacterium sp., Tissierella sp. and Peptostreptococcus sp. were detected in the water samples but not in crude oil samples. Using an archaea-specific primer set, methanogens related to Methanomicrobials and Methanosarcinales were found in water samples but not in crude oil samples. The comparability of the microbial communities in the water and crude oil phase during the period of oil gathering and transferring process was 83.3% and 88.2%, respectively, indicating a stable structure of the microbial communities.     

Mycoremediation of crude oil contaminated soil by specific fungi isolated from Dhahran in Saudi Arabia

Crude oil biodegrading microorganism considers the key role for environmental preserving. In this investigation, crude oil biodegrading fungal strains have been isolated in polluted soil of crude-oil at khurais oil ground in Kingdom of Saudi Arabia. Among of 22 fungal isolates, only three isolates reflected potential capability for oil degradation. These isolates were identified and submitted to GenBank as (A1) Aspergillus polyporicola (MT448790), (A2) Aspergillus spelaeus (MT448791) and (A3) Aspergillus niger (MT459302) through internal-transcribed spacer-regions (ITS1&ITS2) for sequencing in molecular marker. Comparing with controls, strain (A1) Aspergillus niger was superior for biodegradation ability (58%) comparing with Aspergillus polyporicola and Aspergillus spelaeus degrading were showed 47 and 51% respectively. Employed CO₂ evolution as indicator for petroleum oil biodegradation by the fungal isolates reflected that, Aspergillus niger emission highest CO2 (28.6%) comparing with Aspergillus spelaeus and Aspergillus polyporicola which showed 13% and 12.4% respectively. capability of Aspergillus sp. to tolerate and adapted oil pollutants with successful growth rate on them, indicated that it can be employed as mycoremediation agent for recovering restoring ecosystem when contaminated by crude oil.     

Selection of functional consortium for crude oil-contaminated soil remediation

Microorganisms with high oil-degrading performance are essential for bioremediation of soil contaminated with crude oil. A positive end dilution method was employed for the selection of crude oil-degrading functional consortium from contaminated soil. The selected consortium was consisted of Rhizobiales sp., Pseudomonas sp., Brucella sp., Bacillus sp., Rhodococcus sp., Microbacterium sp. and Roseomonas sp. and removed nearly 52.1% of crude oil at initial concentration of 10,000 mg l⁻¹ at 30 °C within 7 days, with removal of aliphatic hydrocarbons by 71.4% and aromatic hydrocarbons by 36.0%, respectively. The effectiveness of the consortium for bioaugmentation was confirmed with microcosm test by contaminated soil (1.0 kg) from Karemary Oilfield, China. The removal efficiency of crude oil was enhanced to >50% in microcosms with the consortium compared with 8-13% or lower in controls over a 60 day period. The crude oil removal reaction was probably first order reaction and the rate was greatly enhanced by bioaugmentation. Supplementation of nitrogen and phosphate sources had limited effect on the oil removal in the tested soil.     

Sensitivity of US Gulf of Mexico coastal marsh vegetation to crude oil: Comparison of greenhouse and field responses

Greenhouse and field studies were conducted to evaluate the effect of crude oil on selected US Gulf of Mexico coastal marsh species. Species showed different levels of sensitivity to oiling between greenhouse and field conditions. In greenhouse studies, two crude oils were used: South Louisiana crude oil (SLC) and Arabian Medium crude oil (AMC). The majority of Spartina patens plants died within one month following oiling with little or no recovery after three months. Panicum hemitomon and Spartina alterniflora were also adversely affected by oiling under greenhouse conditions but to a lesser extent than S. patens. The SLC or AMC oiling led to biomass reductions in S. alterniflora and S. patens. The dry biomass was not affected by oiling in P. hemitomon, Sagittaria lancifolia, Typha latifolia, and Scirpus olneyi. Results showed that S. patens plants were more sensitive to SLC as compared to AMC oil. Gross CO₂-C fixation data collected in the greenhouse indicated no differences in recovery among species across oiling treatments for S. lancifolia, S. olneyi, and T. latifolia. Field studies with S. alterniflora, S. patens and S. lancifolia demonstrated initial sensitivity of these species to oiling, and recovery following oiling with SLC. Our data also showed that caution must be employed whenever results from greenhouse studies are extrapolated to predict oil impact on vegetation under field conditions. Development of any sensitivity index of plant responses to oiling should not be based on greenhouse experiments only. Field evaluations should be included which best depict plant responses to oiling. Thus, restoration measures of US Gulf of Mexico coastal marshes following oiling should rely primarily on field studies. The field research suggests that the US Gulf of Mexico coastal marsh vegetation are likely to recover from oil spills naturally without the need for remediation procedures.     

Microbial biosurfactant mediated removal and/or solubilization of crude oil contamination from soil and aqueous phase: An approach with Bacillus licheniformis MTCC 5514

This study highlights the role of marine microbial biosurfactants on solubilization/removal of crude-oil contamination from four different soils in an aqueous phase. Soil of four different types, viz., sandy, fine sand soil, clay, and clay loam, were collected and saturated with crude oil. Marine isolate MTCC 5514 (Bacillus licheniformis) was chosen for the study and comparisons were made with synthetic surfactants and commercially available biosurfactant. In-situ studies were carried out with different percentages of crude oil to assess the growth and the percentage removal of oil. For ex-situ studies, soils were pre-saturated with crude oil and then treated with the chosen biosurfactant at a 10% concentration level using flask and column methods. After time intervals of 30–120 min, samples were collected and then subjected to extraction with hexane and the percentage removal was calculated. Results revealed, at 2% concentration of crude oil, that complete solubilization was achieved. With regard to ex-situ studies, clay soil absorbed the maximum percentage of oil compared to other soil types, and with regard to the removal, all the synthetic surfactants showed <60% removal irrespective of soil type. In the case of biosurfactants even at 10% concentration, >85% removal was achieved.     

Integrated diversity analysis of the microbial community in a reverse osmosis system from a Brazilian oil refinery

Oil refineries are known for the large volume of water used in their processes, as well as the amount of wastewater generated at the end of the production chain. Due to strict environmental regulations, the recycling of water has now become a viable alternative for refineries. Among the many methods available to treat wastewater for reuse, the use of membranes in reverse osmosis systems stands out due to several economic and environmental benefits. However, these systems are vulnerable to contamination and deposition of microorganisms, mainly because of the feedwater quality. In this study, the microbial diversity of feedwater and reverse osmosis membranes was investigated using a combination of culture-dependent and culture-independent methods in order to characterize the microorganisms colonizing and deteriorating the membranes. In total, 37 bacterial isolates, 17 filamentous fungi and approximately 400 clones were obtained and analyzed. Among the bacterial genera identified, the most represented were Sphingobium, Acidovorax, Microbacterium, Rhizobium and Shinella. The results revealed genera that acted as candidate key players in initial biofilm formation in membrane systems, and provided important information concerning the microbial ecology of oligotrophic aquatic systems.     

Microbial selective plugging and enhanced oil recovery

Summary The ability of indigenous populations of microorganisms in Berea sandstone to improve the volumetric sweep efficiency and increase oil recovery by in situ growth and metabolism following the injection of nutrients was studied. Cores of differing permeabilities connected in parallel without crossflow and slabs of sandstone with differing permeabilities in capillary contact to allow crossflow were used. The addition of a sucrosenitrate mineral salts medium stimulated the growth and metabolism of microorganisms in the sandstone systems. This resulted in a preferential decrease in permeability in the core or slab with the higher initial permeability, diverted flow into the lower-permeability core or slab and improved the volumetric sweep efficiency. Injectivity into the slab with the lower initial permeability in the crossflow system increased during subsequent nutrient injections. Thus, microbial selective plugging does occur in laboratory systems that have the complex flow patterns observed in petroleum reservoirs without losing the ability to inject fluids into the formation. In situ microbial growth and metabolism increased oil recovery 10 to 38% of the original oil in place. Biogenic gas production accompanied oil production, and much of the gas was entrained within the produced oil suggesting that gas production was an important factor leading to increased oil recovery. Quantitation of the amount of phospholipid in the core confirmed that microbial growth preferentially occurred throughout the core with the higher initial permeability. These data showed that in situ microbial growth in the high-permeability regions improved not only the volumetric sweep efficiency but also the microscopic oil displacement efficiency.     

Hydrocarbon bioremediation of a mineral-base contaminated waste from crude oil extraction by indigenous bacteria

The susceptibility to bioremediation of the hydrocarbons contained in a waste from crude oil extraction was examined. Laboratory scale batch reactors were inoculated with indigenous bacteria and biodegradation was followed for 45 days. The total hydrocarbon content was reduced to 70% of its initial value at the end of the experiments. Saturated and aromatic hydrocarbons were the most readily degraded fractions with, respectively, 70% and 60% of the fraction remaining at the end of the experiment. A minor degradation was observed in the resins fraction (20%), whereas the asphaltenes fraction remained almost constant.The substrate preferences of the natural population towards various fractions of the crude oil were determined by both the length of the lag phase and the slope of the exponential growth in a mineral salt-base medium containing either of the different hydrocarbon fraction as the sole source of carbon. The highest consumption rate for every fraction during the time course experiments was in agreement with the shortest lag phase and the greatest exponential growth slope in the corresponding selective media, indicating changes in the population composition.     

Effects of a crude oil spill on water quality and macrobenthos of a southeast Texas stream

On December 6, 1981 an oil spill of 160 barrels (25 440 liters) occurred in a small southeast Texas stream.Water quality changes, other than the presence of oil, were not evident until six months later when water temperature increased and stream flow ceased. This resulted in decreased dissolved oxygen and increased carbon dioxide concentrations. Responses of the benthic macroinvertebrate community included an increase in density of oligochaetes, decrease in numbers and taxa of chironomids, with eventual complete elimination, and low community diversity (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciikaiqacs% gagaqeaiaacMcaaaa!3848!\[(\bar d)\]). Decrease in oil concentration resulted in reversal of these responses. No clean water taxa were collected and complete recovery had not occurred 26 months after the spill when the study was terminated.     

Effects of nitrogen source on crude oil biodegradation

Summary The effects of NH₄Cl and KNO₃ on biodegradation of light Arabian crude oil by an oil-degrading enrichment culture were studied in respirometers. In poorly buffered sea salts medium, the pH decreased dramatically in cultures that contained NH₄Cl, but not in those supplied with KNO₃. The ammonia-associated pH decline was severe enough to completely stop oil biodegradation as measured by oxygen uptake. Regular adjustment of the culture pH allowed oil biodegradation to proceed normally. A small amount of nitrate accumulated in all cultures that contained ammonia, but nitrification accounted for less than 5% of the acid that was observed. The nitrification inhibitor, nitrapyrin, had no effect on the production of nitrate or acid in ammonia-containing cultures. When the culture pH was controlled, either by regular adjustment of the culture pH or by supplying adequate buffering capacity in the growth medium, the rate and extent of oil biodegradation were similar in NH₄Cl- and KNO₃-containing cultures. the lag time was shorter in pH-controlled cultures supplied with ammonia than in nitrate-containing cultures.     

Aminotransferases in the bivalve mollusc Mytilus edulis L. and short term effects of crude oil in brackish water

Transaminases are among the crucial enzymes in amino acid metabolism, which in aquatic organisms is known to be affected by exposure to oil hydrocarbons. The transamination reactions in Mytilus edulis L. were studied to estimate their adequacy to indicate short term oil exposure in mussels. The transamination reactions were measured using paper chromatography and spectrophotometry. A high degree of transamination was observed between 2 oxoglutarate and alanine, aspartate and ornithine. A slight degree of transamination was shown with methionine, leucine, isoleucine, phenylalanine, serine, tryptophan, threonine, tyrosine and valine. No transamination was observed between 2 oxoglutarate and glycine, arginine, histidine, lysine, proline, citrulline and alanine. The effect of the water accommodated fraction WAF of crude oil on selected transaminase reactions was measured. The highest changes during the WAF exposure were mostly observed in the gills and mantle. Alanine aminotransferase EC 2.6.1.2 activity in the mantle was, at its highest, 55 over the control. Aspartate aminotransferase EC 2.6.1.1 activity increased in the gills by 52 . For ornithine transamination, in the gills the highest increase was by 75 and in the mantle by 50 . The metabolic pathways involved in the alterations of aminotransferase activities are discussed. It is concluded that ornithine transamination in gills is a potential indicator for short term crude oil exposure in Mytilus edulis. More studies are needed to evaluate the effects of other organic pollutants on ornithine transamination.     

Aminotransferases in the bivalve mollusc Mytilus edulis L. and short term effects of crude oil in brackish water

Transaminases are among the crucial enzymes in amino acid metabolism, which in aquatic organisms is known to be affected by exposure to oil hydrocarbons. The transamination reactions in Mytilus edulis L. were studied to estimate their adequacy to indicate short term oil exposure in mussels. The transamination reactions were measured using paper chromatography and spectrophotometry. A high degree of transamination was observed between 2 oxoglutarate and alanine, aspartate and ornithine. A slight degree of transamination was shown with methionine, leucine, isoleucine, phenylalanine, serine, tryptophan, threonine, tyrosine and valine. No transamination was observed between 2 oxoglutarate and glycine, arginine, histidine, lysine, proline, citrulline and alanine. The effect of the water accommodated fraction WAF of crude oil on selected transaminase reactions was measured. The highest changes during the WAF exposure were mostly observed in the gills and mantle. Alanine aminotransferase EC 2.6.1.2 activity in the mantle was, at its highest, 55 over the control. Aspartate aminotransferase EC 2.6.1.1 activity increased in the gills by 52 . For ornithine transamination, in the gills the highest increase was by 75 and in the mantle by 50 . The metabolic pathways involved in the alterations of aminotransferase activities are discussed. It is concluded that ornithine transamination in gills is a potential indicator for short term crude oil exposure in Mytilus edulis. More studies are needed to evaluate the effects of other organic pollutants on ornithine transamination.     

纳米技术处理石油污染的研究进展

本文综述了纳米TiO2光催化技术对石油污染物中多种具有代表性的污染物光催化降解研究状况及其在石油污染处理应用中的研究概况,以及目前尚存在的一些问题,列举了近些年来关于利用光催化技术处理石油污染研究的部分成果,认为在未来的研究中应该集中在反应机理、光响应范围和量子效率高的催化剂制备等方面。     

Contamination of food products with Mycobacterium avium paratuberculosis: a systematic review

Although a causal link between Mycobacterium avium subspecies paratuberculosis (MAP) and Crohn's disease has not been proved, previous studies suggest that the potential routes of human exposure to MAP should be investigated. We conducted a systematic review of literature concerning the likelihood of contamination of food products with MAP and the likely changes in the quantity of MAP in dairy and meat products along their respective production chains. Relevant data were extracted from 65 research papers and synthesized qualitatively. Although estimates of the prevalence of Johne's disease are scarce, particularly for non-dairy herds, the available data suggest that the likelihood of contamination of raw milk with MAP in most studied regions is substantial. The presence of MAP in raw and pasteurized milk has been the subject of several studies which show that pasteurized milk is not always MAP-free and that the effectiveness of pasteurization in inactivating MAP depends on the initial concentration of the agent in raw milk. The most recent studies indicated that beef can be contaminated with MAP via dissemination of the pathogen in the tissues of infected animals. Currently available data suggests that the likelihood of dairy and meat products being contaminated with MAP on retail sale should not be ignored.     

Biostimulation potential of biochar for remediating the crude oil contaminated soil and plant growth

Crude oil contamination is a serious environmental threat to soil and plants growing in it. Biochar has the potential of biostimulation for remediation of crude oil-contaminated soil. Therefore, the current research was designed to analyze the bio-stimulatory impact of biochar for remediating the crude oil contaminated soil (10%, and 15%), and growth of maize under glasshouse conditions. Biochar was produced by pyrolysis of Australian pines at 350 °C. Soil incubations were done for 20 days. The results of soil analysis showed that the crude oil degradation efficiency of biochar was 34%. The soil enzymatic activities had shown 38.5% increase in fluorescein diacetate (FDA) hydrolysis and 55.6% increase in dehydrogenase activity in soil incubated with biochar in comparison to control. The soil microbial diversity was improved to 41% in biochar treated soil with respect to untreated one, while microbial respiration rate had shown a 33.67% increase in soil incubated with biochar with respect to control under oil stress. Gas Chromatography Mass spectrometry (GC-MS) analysis had shown the high content of low molecular weight hydrocarbons (C₉-C₁₃) in the soil incubated with biochar in comparison to untreated soil. Biochar showed a significant increase in fresh and dry biomass (25%, 14.61%), leaf area (10%), total chlorophyll (11%), water potential (21.6%), osmotic potential (21%), and membrane stability index (12.7%). Moreover, biochar treatment showed a higher increase in the contents of proline (29%), total amino acids (18%), soluble sugars (30.4%), and antioxidant enzymes like superoxide dismutase (16.5%), catalase (11%), and peroxidase (12%). Overall, the results of the present study suggest the bio-stimulating potential of biochar for degradation of hydrocarbons in crude oil contaminated soil and their growth-stimulating effects on maize.     

Statistical optimization of crude oil bio-degradation by a local marine bacterium isolate Pseudomonas sp. sp48

Pseudomonas sp. sp48, a marine bacterium isolated from Bahary area (Alexandria, Egypt), showed a high potency for oil degradation up to 1.5%. Additionally, it showed an ability to consume aromatic hydrocarbons (phenol & naphthalene) and aliphatic (pentadecane) reaching to 79; 73; 62%, respectively. In the current study, Plackett-Burman factorial design was applied to evaluate culture conditions affecting the degradation potency. Analysis of Plackett-Burman design results revealed that, the most significant variables affecting oil removal were magnesium sulfate, inoculum size, glucose and Triton X-100. To optimize the levels of these significant variables Response Surface Methodology (RSM) was followed. In this respect, the three-level Box–Behnken design was employed and a polynomial model was created to correlate the relationship between the three variables and oil removal. The optimal combinations of the major constituents of media that was evaluated from the non-linear optimization algorithm of EXCEL-Solver was as follows: (w/v%) 1 crude oil, 0.5 peptone, 0.5 yeast-extract, 1 ammonium chloride, 0.7418 D-glucose, 0.5 MgSO₄·7H₂O, 0.1 Triton X-100 and inoculums size 4.18?ml% in natural sea water at pH 7; 30?°C incubation temperature, 200?rpm for 6?days. The predicted optimum oil removal was 89%, which is 2.4 times more than the basal medium.     

一株原油降解菌的分离鉴定及降解特性研究

[目的]对从大连湾原油污染海域生长的海绵中分离的原油降解菌2-9进行鉴定及降解特性研究.[方法]采用16S rRNA基因序列同源性分析、生理生化指标测定、DNAG+C含量测定、全细胞脂肪酸组成测定、碳源利用实验等多种方法对该菌株进行鉴定,并通过降解实验测定其对原油的降解情况.[结果]菌株2-9鉴定为Nitratireductor basaltis,革兰氏阴性,接触酶和氧化酶阳性.在GenBank中与其16S rRNA基因序列相似度最高的模式株为Nitratireductor basaltis J3T,相似性为99％.可生长的pH范围为6.0-10.0,最适生长pH值为8.0;可生长温度范围为15℃-42℃,最适生长温度为30℃; NaCl浓度生长范围是0-8％(W/V),最适生长盐度为2％.该菌株可以利用多种糖和有机酸的碳源,其DNA G+C含量为57.29 mol％,主要脂肪酸组成为ω7c-十八碳单不饱和脂肪酸(63.61％)、ω8c型环式十九碳饱和脂肪酸(16.97％)、饱和十八碳脂肪酸(4.28％)和十六碳饱和脂肪酸(3.39％).同时,考察了该菌株对原油的降解效果,在人工海水培养基中,14d内对原油(初始浓度为1 g/L)的平均降解率为63.5％.[结论]菌株2-9是一株具有开发潜力的原油降解菌.     

Phylogenetic diversity of bacterial communities associated with bioremediation of crude oil in microcosms

Bioremediation, mainly by indigenous bacteria, has been regarded as an effective way to clean up oil pollution after an oil spill. In order to obtain a systematic understanding of the succession of bacterial communities associated with oil bioremediation, sediments collected from the Penglai 19-3 oil platform were co-incubated with crude oil. Oil biodegradation was assessed on the basis of changes in oil composition monitored by GC–MS. Changes in the bacterial community structure were detected by two 16S rRNA gene based culture-independent methods, denaturing gradient gel electrophoresis (DGGE) and clone library. The results suggested that crude oil was rapidly degraded during the 30-day bioremediation period. Bacteria affiliated with the genus Pseudomonas dominated all three clone libraries. But dramatic changes were also detected in the process of biodegradation of crude oil. The “professional hydrocarbonocastic bacteria” (e.g., Alcanivorax) became abundant in the two samples during the bioremediation period. Meanwhile, δ-proteobacteria was only detected in the two samples. Information on the bacterial community revealed in this study will be useful in developing strategies for bioremediation of crude oil dispersed in the marine ecosystem.