Biodeterioration of Incralac used for the protection of bronze monuments

Outdoor bronze sculptures are highly susceptible to corrosion in many environments and organic coatings are widely used for their protection. The purpose of this study was to determine the susceptibility of the commonly used coating Incralac to biodeterioration by microorganisms. A yeast was isolated from a bronze statue treated with Incralac and its ability to degrade Incralac was determined using growth curves, scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The organism grew slowly on Incralac in liquid culture, but SEM images demonstrated its ability to adhere to Incralac coated metal. Additionally, the yeast caused a rapid drop in the low frequency impedance of Incralac coated metal that was not observed under sterile conditions, indicating that the organism accelerated deterioration of the coating. The potential for microbial growth to accelerate deterioration of Incralac should be considered when developing a maintenance strategy for the protection of outdoor metal monuments.     

微生物降解有机磷农药的研究进展

果蔬菜等农产品有机磷农药残留越来越严重,利用微生物降解有机磷农药,在改善环境和人们生活质量方面已显得经济而有效。本文就降解有机磷农药的微生物种类,降解机制及编码降解酶的相应基因,以及工程菌的构建作了综述。     

微生物在矿物浮选分离领域应用进展

研究微生物及其代谢产物与矿物的相互作用是开发新的生物选矿药剂的基础。文章主要从微生物的菌体本身及其微生物所产生的胞外聚合物与矿物之间发生的吸附、沉淀、絮凝等作用方面做出了综合性叙述,并对它们的作用机理做了总结性的介绍,为生物浮选的应用研究提供参考。     

不同种植模式对烟田土壤微生物数量的影响

通过对毕节市赫章六曲不同烤烟种植模式土壤中微生物的数量的实验,结果发现：套种模式下,土壤微生物的数量与对照相比,存在极显著的差异,而且套种并还田的种植模式下,对土壤中微生物的数量影响最大。     

行动导向在食品微生物检验技术教学中的应用

本文从食品微生物检验技术的课程特点、教学实际,以及高职院校学生的特点出发、探讨行动导向教学法在该课程教学上应用的优势,并举例分析和说明了行动导向教学法中案例分析法、模拟教学法、团队竞争法和项目分析法等具体方法在食品微生物检验技术教学中的具体应用和优点.同时本文就行动导向教学法具体实施过程中遇到的一些客观问题进行了分析.     

有效微生物群对水仙花生长的影响

水仙花鳞茎喷施有效微生物群制剂 ,能促进其生长发育 ,使水仙花的根数、根长、叶绿素含量增加 ,而且显著提高了叶片的长度和宽度 ,尤其以 2 0 0 0倍稀释液的效果最佳。     

EM中絮凝剂产生菌筛选的试验研究

通过对EM的定向培养试验，筛选出光合细菌、酵母菌两种絮凝剂产生菌。最佳接种量试验表明：定向培养时，光合细菌的接种量为5％，酵母菌的接种量为3％时，培养效果最好。     

Changes in freshwater sediment microbial populations during fermentation of crude glycerol

BackgroundThis work studied how the exposure to an unusual substrate forced a change in microbial populations during anaerobic fermentation of crude glycerol, a by-product of biodiesel production, with freshwater sediment used as an inoculum.ResultsThe microbial associations almost completely (99.9%) utilized the glycerol contained in crude glycerol 6 g L⁻¹ within four days, releasing gases, organic acids (acetic, butyric) and alcohols (ethanol, n-butanol) under anaerobic conditions. In comparison with control medium without glycerol, adding crude glycerol to the medium increased the amount of ethanol and n-butanol production and it was not significantly affected by incubation temperature (28 °C or 37 °C), nor incubation time (4 or 8 d), but it resulted in reduced amount of butyric acid. Higher volume of gas was produced at 37 °C despite the fact that the overall bacterial count was smaller than the one measured at 20 °C. Main microbial phyla of the inoculum were Actinobacteria, Proteobacteria and Firmicutes. During fermentation, significant changes were observed and Firmicutes, especially Clostridium spp., began to dominate, and the number of Actinobacteria and Gammaproteobacteria decreased accordingly. Concentration of Archaea decreased, especially in medium with crude glycerol. These changes were confirmed both by culturing and culture-independent (concentration of 16S rDNA) methods.ConclusionsCrude glycerol led to the adaptation of freshwater sediment microbial populations to this substrate. Changes of microbial community were a result of a community adaptation to a new source of carbon.How to cite: Paiders M, Nikolajeva V, Makarenkova G, et al. Changes in freshwater sediment microbial populations during fermentation of crude glycerol. Electron J Biotechnol 2021;49. https://doi.org/10.1016/j.ejbt.2020.10.007     

Enzymatic decolorization of bacterial pigments from culturally significant marble

Marble monuments and facades are susceptible to microbial colonization. Microbial growth on a marble surface can develop into unsightly red stains whose removal has proven problematic. The purpose of this study was to determine if the red-brown stains on Isamu Noguchi's marble sculpture Slide Mantra (1991) could be caused by pigment-producing microorganisms and to assess the potential of enzymatic stain remediation. Traditional cell culture methods were used to isolate a pigmented bacterium from a stained area of the sculpture. Sequencing and analysis of the 16S rRNA gene identified the organism as a strain of Serratia marcescens, and FT-IR spectroscopy demonstrated that the pigment produced by the bacteria was most likely a prodigiosin. Decolorization of the pigment in solution demonstrated that the enzyme laccase from the fungus Trametes versicolor has potential as a decolorizing agent. This study suggests that enzymatic decolorization may be applicable to stains on culturally significant marble caused by microbial colonization.