Advantages of using microbial technology over traditional chemical technology in removal of black crusts from stone surfaces of historical monuments

This study compares two cleaning methods, one involving an ammonium carbonate-EDTA mixture and the other involving the sulfate-reducing bacterium Desulfovibrio vulgaris subsp. vulgaris ATCC 29579, for the removal of black crust (containing gypsum) on marble of the Milan Cathedral (Italy). In contrast to the chemical cleaning method, the biological procedure resulted in more homogeneous removal of the surface deposits and preserved the patina noble under the black crust. Whereas both of the treatments converted gypsum to calcite, allowing consolidation, the chemical treatment also formed undesirable sodium sulfate.     

Advantages of Using Microbial Technology over Traditional Chemical Technology in Removal of Black Crusts from Stone Surfaces of Historical Monuments

This study compares two cleaning methods, one involving an ammonium carbonate-EDTA mixture and the other involving the sulfate-reducing bacterium Desulfovibrio vulgaris subsp. vulgaris ATCC 29579, for the removal of black crust (containing gypsum) on marble of the Milan Cathedral (Italy). In contrast to the chemical cleaning method, the biological procedure resulted in more homogeneous removal of the surface deposits and preserved the patina noble under the black crust. Whereas both of the treatments converted gypsum to calcite, allowing consolidation, the chemical treatment also formed undesirable sodium sulfate.     

The Detection of Microorganisms and Organic Material on Stainless Steel Food Contact Surfaces

Few methods are available for the differentiation of microorganism and organic material on surfaces, although such mixtures are commonplace, particularly in the food industry, where food debris (soil) and microorganisms frequently foul food contact surfaces and pose challenges in terms of hygiene and cleanability. It would be of value to discern any differences in removal or persistence on surfaces. This review considers some methods which are available. Direct epifluorescence microscopy (DEM) enables visual differentiation, but traditional microbiological culture methods cannot detect organic soil. Atomic force microscopy (AFM) provides images of the surface on the nanometer scale, with minimal preparation, and is able to visualise both cellular and acellular components of the mixture, particularly prior to cleaning. Confocal laser scanning microscopy (CLSM) also has potential in this area. Surface sensitive methods such as X-Ray photoelectron spectroscopy (XPS) and Time-of-flight secondary ion mass spectrometry (ToFSIMS) provide information on chemical species present on a surface. Those chemical species more likely on microbial cells may be differentiated from those more likely in a specified organic soil, thus comparisons may be made as to differential removal of the organic soil and microbial cells. These methods may be of value in studies on the fouling and cleanability of surfaces.     

Feasibility of Removing Surface Deposits on Stone Using Biological and Chemical Remediation Methods

The study was conducted on alterations found on stone artwork and integrates microbial control and a biotechnological method for the removal of undesirable chemical substances. The Demetra and Cronos sculptures are two of 12 stone statues decorating the courtyard of the Buonconsiglio Castle in Trento (Italy). An initial inspection of the statues revealed putative black crusts and highlighted the microbial contamination causing discoloration. In 2006, the Cultural Heritage Superintendence of Trento commissioned us to study and remove these chemical and biological stains. Stereomicroscopy characterised the stone of the sculptures as oolitic limestone, and infrared analyses confirmed the presence of black crusts. To remove the black crusts, we applied a remediation treatment of sulphate-reducing bacteria, which removes the chemical alteration but preserves the original stone and the patina noble. Using traditional and biomolecular methods, we studied the putative microbial contamination and confirmed the presence of biodeteriogens and chose biocide Biotin N for the removal of the agents causing the discolouration. Denaturing gradient gel electrophoresis fluorescent in situ hybridisation established that Cyanobacteria and green algae genera were responsible for the green staining whereas the black microbial contamination was due to dematiaceous fungi. After the biocide Biotin N treatment, we applied molecular methods and demonstrated that the Cyanobacteria, and most of the green algae and dematiaceous fungi, had been efficiently removed. The reported case study reveals that conservators can benefit from an integrated biotechnological approach aimed at the biocleaning of chemical alterations and the abatement of biodeteriogens.     

Biological color stripping: A novel technology for removal of dye from cellulose fibers

This research work was carried out to compare the color stripping efficiency of optimized biological method with the chemical stripping, commonly employed in the textile industries. Knitted fabric dyed with Reactive black B dye in 2, 4 and 6% shades strengths was subjected to chemical and biological stripping processes individually. Biological stripping process was found many fold superior to chemical one. It was noted that shade strength does not showed any pronounced effect on the bursting strength of fabric but biological and chemical treatment affect the quality of fabrics in terms of bursting strength/durability of fabric. White rot fungus Ganoderma lucidum IBL-05 showed good potential for decolorization/color stripping of cotton fabric dyed with Reactive black B under optimized set of conditions. The chemical stripping technology is inferior to biological stripping process regarding the quality of fabric and percent color removal from cotton fabric dyed with Reactive black B dye.     

A natural experiment on the condition-dependence of achromatic plumage reflectance in black-capped chickadees

Honest advertisement models posit that only individuals in good health can produce and/or maintain ornamental traits. Even though disease has profound effects on condition, few studies have experimentally tested its effects on trait expression and even fewer have identified a mechanistic basis for these effects. Recent evidence suggests that black and white, but not grey, plumage colors of black-capped chickadees (Poecile atricapillus) are sexually selected. We therefore hypothesized that birds afflicted with avian keratin disorder, a condition that affects the beak and other keratinized tissues, would show reduced expression of black and white, but not grey, color. UV-vis spectrometry of black-capped chickadees affected and unaffected by avian keratin disorder revealed spectral differences between them consistent with this hypothesis. To elucidate the mechanistic bases of these differences, we used scanning electron microscopy (SEM), electron-dispersive x-ray spectroscopy (EDX) and a feather cleaning experiment. SEM showed extreme feather soiling in affected birds, and EDX revealed that this was most likely from external sources. Experimentally cleaning the feathers increased color expression of ornamental feathers of affected, but not unaffected, birds. These data provide strong evidence that black and white color is an honest indicator in chickadees, and that variation in feather dirtiness, likely due to differences in preening behavior is a mechanism for this association.     

Evaluation of cleaning strategies for removal of biofilms from reverse-osmosis membranes

An evaluation was made of the efficiency of five classes of chemical cleaning agents for removing biofilm from spirally wound cellulose acetate reverse-osmosis membranes receiving influent with high or low levels of combined chlorine. Each cleaning regimen utilized one or more of the following types of chemical: (i) surfactants and detergents, (ii) chaotropic agents, (iii) bactericidal agents, (iv) enzymes, and (v) antiprecipitants. Cleaning efficiency was tested in the laboratory on membrane material removed from operations at various intervals (2 to 74 days). Cleaning effectiveness was evaluated against nontreated control membranes and was scored by scanning electron microscopy and enumeration of surviving bacteria after treatment of the membranes. The combinations of classes which were most effective in biofilm removal were the anionic and chaotropic agent combination and combinations involving enzyme-containing preparations. Membranes receiving influent with high levels of combined chlorine were easier to clean but more susceptible to structural damage from prolonged exposure to combined chlorine. No treatment or combination of treatments was completely effective or effective at all stages of biofilm development.     

Improved Methodology for Bioremoval of Black Crusts on Historical Stone Artworks by Use of Sulfate-Reducing Bacteria

An improved methodology to remove black crusts from stone by using Desulfovibrio vulgaris subsp. vulgaris ATCC 29579, a sulfate-reducing bacterium, is presented. The strain removed 98% of the sulfates of the crust in a 45-h treatment. Precipitation of black iron sulfide was avoided using filtration of a medium devoid of iron. Among three cell carriers, Carbogel proved to be superior to both sepiolite and Hydrobiogel-97, as it allowed an easy application of the bacteria, kept the system in a state where microbial activity was maintained, and allowed easy removal of the cells after the treatment.     

Regime shift and microbial dynamics in a sequencing batch reactor for nitrification and anammox treatment of urine

The microbial population and physicochemical process parameters of a sequencing batch reactor for nitrogen removal from urine were monitored over a 1.5-year period. Microbial community fingerprinting (automated ribosomal intergenic spacer analysis), 16S rRNA gene sequencing, and quantitative PCR on nitrogen cycle functional groups were used to characterize the microbial population. The reactor combined nitrification (ammonium oxidation)/anammox with organoheterotrophic denitrification. The nitrogen elimination rate initially increased by 400%, followed by an extended period of performance degradation. This phase was characterized by accumulation of nitrite and nitrous oxide, reduced anammox activity, and a different but stable microbial community. Outwashing of anammox bacteria or their inhibition by oxygen or nitrite was insufficient to explain reactor behavior. Multiple lines of evidence, e.g., regime-shift analysis of chemical and physical parameters and cluster and ordination analysis of the microbial community, indicated that the system had experienced a rapid transition to a new stable state that led to the observed inferior process rates. The events in the reactor can thus be interpreted to be an ecological regime shift. Constrained ordination indicated that the pH set point controlling cycle duration, temperature, airflow rate, and the release of nitric and nitrous oxides controlled the primarily heterotrophic microbial community. We show that by combining chemical and physical measurements, microbial community analysis and ecological theory allowed extraction of useful information about the causes and dynamics of the observed process instability.     

Identification of some of the major groups of bacteria in efficient and nonefficient biological phosphorus removal activated sludge systems.

To investigate the bacteria that are important to phosphorus (P) removal in activated sludge, microbial populations were analyzed during the operation of a laboratory-scale reactor with various P removal performances. The bacterial population structure, analyzed by fluorescence in situ hybridization (FISH) with oligonucleotides probes complementary to regions of the 16S and 23S rRNAs, was associated with the P removal performance of the reactor. At one stage of the reactor operation, chemical characterization revealed that extremely poor P removal was occurring. However, like in typical P-removing sludges, complete anaerobic uptake of the carbon substrate occurred. Bacteria inhibiting P removal overwhelmed the reactor, and according to FISH, bacteria of the beta subclass of the class Proteobacteria other than beta-1 or beta-2 were dominant in the sludge (58% of the population). Changes made to the operation of the reactor led to the development of a biomass population with an extremely good P removal capacity. The biochemical transformations observed in this sludge were characteristic of typical P-removing activated sludge. The microbial population analysis of the P-removing sludge indicated that bacteria of the beta-2 subclass of the class Proteobacteria and actinobacteria were dominant (55 and 35%, respectively), therefore implicating bacteria from these groups in high-performance P removal. The changes in operation that led to the improved performance of the reactor included allowing the pH to rise during the anaerobic period, which promoted anaerobic phosphate release and possibly caused selection against non-phosphate-removing bacteria.     

Microbial trans‐glutaminase enhances the physical and mechanical properties of depigmented wool

This study investigates the effects of enzymatic treatment with microbial trans‐glutaminase (m‐TGase) on the physical and mechanical properties of the depigmented wool yarns. Coarse pigmented wool yarns were treated with iron (II) followed by depigmentation with both oxidative and oxidative‐reductive chemicals. The depigmented wool yarns were then treated with m‐TGase to reduce the negative effects of the harsh chemicals. Diverse features of the wool yarns, including: tensile strength, elongation, color, diameter, moisture content, alkali solubility, and weight reduction, were measured before and after bleaching and enzymatic treatments. The treatment with the oxidative and reductive agents led to reduced tensile strength and elongation, and increased lightness, alkali solubility, and moisture content of the yarns. In contrast, the enzymatic treatment by m‐TGases cross‐linked the proteins of wool fibers via reaction between glutamine and lysine isodipeptide remediated the wool yarns. This improved the tensile strength and elongation and decreased the alkali solubility and moisture content. Fourier transform infrared spectroscopy (FTIR) was used to follow the chemical changes in wool fibres during depigmentation and enzymatic treatments.     

连续施肥对农田黑土微生物功能多样性的影响

应用Biolog Eco微平板培养法研究了中国科学院海伦农业生态试验站20余年连续不同施肥处理(对照、氮磷钾、氮磷钾+秸秆、氮磷钾+猪粪1、氮磷钾+猪粪2和氮磷钾+猪粪3)下土壤微生物代谢功能多样性的变化。结果表明:长期施肥条件下,单施化肥和有机肥与化肥配施对土壤细菌、真菌数量影响不明显,但高量有机肥与化肥配施可以显著增加放线菌数量。Biolog结果表明,施用有机肥的平均颜色变化率高于单施化肥和对照。Shannon指数、Simpson指数和McIntosh指数均是有机肥和化肥配施高于化肥单施与对照。主成分分析结果表明,对照、NPK与其他几种处理有较明显的距离,说明有机肥的连年施用导致了土壤微生物代谢功能多样性的变化。     

东北黑土结皮发育过程

基于模拟降雨试验,从微结构、容重、抗剪强度角度分析了降雨过程中东北黑土结皮的发育过程特征,并探讨了黑土结皮的发育对土壤入渗的影响.结果表明：随着降雨的进行,东北黑土的表层结构逐渐致密,容重、抗剪强度不断增加,入渗能力下降;120 min降雨历时内,黑土发育了厚约3～4 mm的稳定结皮层,结皮发生层孔隙度下降6.45%、容重增加14.13%;消除雨滴打击后（盖网处理）,结皮发育强度减弱,120 min降雨历时内,结皮发生层孔隙度下降3.27%、容重增加7.11%,均小于无盖网处理,但累积入渗量较后者高41.1%.东北黑土结构稳定,雨滴打击是其结皮发育的主导因子,降雨过程中未发现明显的颗粒淋移现象.     

Soil carbon dynamics in a Pinus massoniana plantation following clear-cutting and slash removal

Aims Slash removal is a common practice to prepare recently harvested sites for replanting. However, little is known about its impact on soil carbon (C) dynamics in subtropical plantations. This study evaluates the effects of burning versus manual slash removal site preparation treatments on soil organic carbon (SOC), soil respiration and soil microbial community structure in a Pinus massoniana plantation in southern China.Methods Three areas within a mature P. massoniana plantation were clearcut. Two months following harvesting, slash on one-half of each area was burned (BURN), whereas slash was manually removed (MANR) on the other portion. Slash removal treatments were also compared with adjacent uncut plantation areas (UNCUT). Soil samples, and soil respiration measurements were used to characterize soil properties and microbial communities following slash removal treatments. Important findings Mean soil respiration rates from the MANR and BURN treatments were 26% and 17% lower, respectively, than the UNCUT treatment over 1 year. The MANR and BURN treatment resulted in soils with 27% and 9% reduction in total phospholipid fatty acids (PLFAs) and 18% and 10% reduction in bacterial PLFAs, respectively, compared with the UNCUT treatment. However, no significant differences existed between slash removal treatments with respect to soil chemical properties, SOC chemical compositions, soil respiration and microbial communities; although PLFA patterns were notably different for the burned plots. Most factors affecting C dynamics and microbial communities were not sensitive to the differences imparted to the ecosystem due to manual slash removal or burning. Our results suggested that low-intensity burning after clear-cutting might have no significant effect on soil C pool and its dynamics compared with manual slash removal in subtropical plantations.     

布依族体质特征研究

本文调查了布依族成年人494例(男为259例,女为235例)的体质特征,计算出58项测量项目的均值和标准差、31项指数值和9项观察项目的出现率,并与国内一些群体的体质特征进行了比较,得出布依族的体质特征为:上眼睑皱褶出现率高,男为95 .4%,女为97. 0%。蒙古褶出现率低,男为30. 5%,女为35. 3%。鼻根男多为中等型,女多为低型。鼻翼高度多为中等。多为圆形耳垂。发色多为黑色,眼色多为褐色。男性多为黄色肤色,女性多为浅黄色肤色。圆头型、高头型、阔头型、阔面型、中鼻型、中躯干型、中腿型、中胸型、宽肩型、宽骨盆型出现率最高。男身高均值为158. 6cm,女身高均值为149. 4cm。     

Integrating entrapped mixed microbial cell (EMMC) process for biological removal of carbon and nitrogen from dilute swine wastewater

An entrapped mixed microbial cells (EMMC) process was used to investigate the simultaneous removal of carbon and nitrogen from dilute swine wastewater. Cellulose triacetate was used as the matrix for entrapping the mixed microbial cells. The EMMC process was tested with various oxygen supply conditions (ratios of aeration to non-aeration times) and two types of carrier sizes (large and medium). Also, various pre-treatments with chemical coagulation, screen separation and ammonium crystallization prior to the EMMC process, and post-treatment after the EMMC process were investigated. It was found that at a hydraulic retention time of 30 h and one hour of aeration and one hour of non-aeration, the EMMC process packed with medium carriers after the pretreatment of ammonium crystallization, exhibited the best total nitrogen removal efficiency of 95.1 +/- 1.0% when compared to the other two pre-treatment methods. The total chemical oxygen demand (TCOD) and soluble chemical oxygen demand removal efficiencies were 83.5 +/- 2.2% and 84.1 +/- 1.1%, respectively. Lime post-treatment provided TCOD and total phosphorus removal efficiencies of 59.6 +/- 2.7% and 98.0 +/- 0.5%, respectively. Thus, a cost analysis for ammonium crystallization pre-treatment, EMMC process, and post-treatment with lime was conducted. The unit cost for a 2000 pig operation is approximately dollars 4.91/pig/year. For the application of the EMMC process with the proposed pre- and post-treatments, a suitable farm size needs to be greater than a 2000 pig operation. Because of the high efficiency and the simple operation of simultaneous carbon and nitrogen removal, the EMMC process has the potential for treatment of dilute swine wastewater in a land-limited area and can be manufactured as pre-fabricated wastewater treatment units.     

Repeated batch process for biological treatment of black liquor using brown-rot basidiomycete <Emphasis Type="Italic">Fomitopsis</Emphasis> sp. IMER2

A repeated batch operation is developed for the treatment of alkaline pulp black liquor, through a process of biological acidification precipitation of lignin using brown rot fungus Fomitopsis sp. IMER2. The results showed that COD and color removal of black liquor was dependent on the biomass concentration, pH decrease and initial COD. Based on these results, the repeated batch process was successfully carried out 12 times over 36 days in an air bubble column bioreactor. The average reduction of COD and color was approximately 40% and 70%, respectively.     

DGGE analysis of 16S rDNA of ammonia-oxidizing bacteria in chemical–biological flocculation and chemical coagulation systems

Microbial community DNA was extracted from activated sludge samples taken from a chemical bioflocculation process and a chemical coagulation process in Shanghai, China. 16S rDNA of ammonia-oxidizing bacteria (AOB)was amplified by nested polymerase chain reaction and fingerprinted by denaturing gradient gel electrophoresis for microbial structure analysis. The Shannon diversity index of each sample was determined. The results indicated that the microbial structure of AOB in chemical bioflocculation process was comparable at two operational conditions. The ammonia-oxidizing bacterial communities were similar in three channels of the chemical bioflocculation process and in three serial tanks in the chemical coagulation process at the same condition. The diversity of microbial structures in the chemical bioflocculation process was higher than in the chemical coagulation process, in which the microbial structure was similar to that in the influent. Although the microbial study provides insights to the nitrification removal, higher microbial diversity of AOB does not necessarily mean higher ammonia oxidization. Molecular analysis should be combined with chemical assays to optimize operational conditions.     

From microbial fuel cell (MFC) to microbial electrochemical snorkel (MES): maximizing chemical oxygen demand (COD) removal from wastewater

The paper introduces the concept of the microbial electrochemical snorkel (MES), a simplified design of a “short-circuited” microbial fuel cell (MFC). The MES cannot provide current but it is optimized for wastewater treatment. An electrochemically active biofilm (EAB) was grown on graphite felt under constant polarization in an urban wastewater. Controlling the electrode potential and inoculating the bioreactor with a suspension of an established EAB improved the performance and the reproducibility of the anodes. Anodes, colonized by an EAB were tested for the chemical oxygen demand (COD) removal from urban wastewater using a variety of bio-electrochemical processes (microbial electrolysis, MFC, MES). The MES technology, as well as a short-circuited MFC, led to a COD removal 57% higher than a 1000 Ω-connected MFC, confirming the potential for wastewater treatment.     

From microbial fuel cell (MFC) to microbial electrochemical snorkel (MES): maximizing chemical oxygen demand (COD) removal from wastewater

The paper introduces the concept of the microbial electrochemical snorkel (MES), a simplified design of a "short-circuited" microbial fuel cell (MFC). The MES cannot provide current but it is optimized for wastewater treatment. An electrochemically active biofilm (EAB) was grown on graphite felt under constant polarization in an urban wastewater. Controlling the electrode potential and inoculating the bioreactor with a suspension of an established EAB improved the performance and the reproducibility of the anodes. Anodes, colonized by an EAB were tested for the chemical oxygen demand (COD) removal from urban wastewater using a variety of bio-electrochemical processes (microbial electrolysis, MFC, MES). The MES technology, as well as a short-circuited MFC, led to a COD removal 57% higher than a 1000 Ω-connected MFC, confirming the potential for wastewater treatment.