Metabolic Activity of Micromycetes Affecting Urban Concrete Constructions

Hindawi e Scientiﬁc World Journal Volume 2018, Article ID 8360287, 9 pages https://doi.org/10.1155/2018/8360287 Research Article Metabolic Activity of Micromycetes Affecting Urban Concrete Constructions Galina Yakovleva ,1 Eugene Sagadeev,2 Viktor Stroganov,2 Olga Kozlova,1 Rodion Okunev,1 and Olga Ilinskaya1 Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Kazan, Kremlevskaya Str., , Russia Kazan State University of Architecture and Engineering, Kazan, Zelenaya Str., , Russia Correspondence should be addressed to Galina Yakovleva; yakovleva [email protected] Received 23 August 2018; Accepted 6 November 2018; Published 2 December 2018 Academic Editor: Sanjay Govindwar Copyright © 2018 Galina Yakovleva et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Concrete resistance to the destructive action of microorganisms is considered as a measure of its durability and is increasingly being raised as an important issue. We focused our study on the biodeterioration of concrete specimens widely used as a building material of urban houses by micromycetes isolated from the inner wall surface of the former military hospital in Kazan city, Tatarstan, Russia. Fungal community consists of 9 Penicillium isolates, 6 Aspergillus,2Trichoderma,and1isolateofAlternaria.First,we have identifed two dominant isolates, Aspergillus fumigatus and Penicillium brevicompactum,andcharacterizedtheirdestructive properties according to the radial growth rate, antagonistic activity towards bacterial habitants of concrete, and production of organic acids. Ten, we have demonstrated that fve tested brands of high-strength concrete difer in bioreceptivity. Te alterations in concrete resistances to compression and fexure afer fungal attack were recorded at the trend level, mainly due to a short exposure time of concrete to fungal destructors in tests recommended by national Russian standard. Finally, using scanning electron microscopy we have shown that colonization of concrete by the dominant fungi includes their penetration into the thickness of concrete and germination in cracks. Elementary analysis revealed the decrease of calcium content on about 41% afer fungal growth on the concrete in liquid phase and on 32% by superfcial growth in comparison with the samples without fungal treatment. 1. Introduction concrete materials and accelerating the destruction process [3]. Te infuence of microorganisms on concrete mainly Concrete, a mixture of Portland cement and water, aggregates occurs by eroding a concrete surface. Tis leads to an increase and in some cases admixtures is a building material that in the porosity of concrete, the appearance of cracks, chips, gains strength over time. Biogenic deterioration of the con- and other damage, which ultimately signifcantly reduces the crete traditionally referred to microorganisms. Te causes of life of this material [4]. Te favorable conditions for microbial building material biodeterioration are three main processes: growth on the concrete surfaces are increased humidity (i.e., mechanical, assimilative (building materials are a source of between 60% and 98%), long-term cycles of wetting and nutrition and energy for microorganisms), and dissimila- drying, freezing and thawing, high concentration of carbon − 2− tive (the interaction of building materials with aggressive dioxide, high concentration of Cl or SO4 ions, and a small metabolites of microorganisms) [1]. Te action of microor- amount of acids [5]. Biodeterioration of concrete structures ganisms on concrete structures can be classifed according was demonstrated to be a common occurrence; however, to their efects on concrete surfaces, concrete matrices and various microbial populations and mechanisms were shown on cracking and crack growth [2]. Te growth efects are to play diferent roles at diferent locations [6]. We focused supplemented by chemical action of microbial metabolites our study on the biodeterioration of concrete specimens leading to the alteration of physicochemical properties of widely used as a building material of urban houses. 2 Te Scientifc World Journal Many buildings are believed to have been damaged to .. Concrete Specimens and eir Treatment by Fungi. High varying degrees by microbiologically induced destruction of strength sandy concrete samples M 400, M 500, V 600, V concrete. Until today, there is no clear understanding of the 800, and V 1000 were made in the form of beams with extent and severity of the damage, the operative mechanism, asizeof160×40×40 mm. In the manufacture of cement- and efective remedial techniques for the microbial attack sand mortars based on Portland cement grades PC400 and to concrete structures [7]. Tere is a set of investigations PC500 (strength corresponding to classes B30 and B40) describing concrete biodeterioration in tropical coastal and and concretes of classes B45, B60, and B70 the ratio of marine areas [8, 9], Coombes, 2016, but little is known about sand (fraction 0.5-0.25 mm corresponding to Russian state this process in cities located in temperate-continental climate standard GOST 8736-93) and cement was three to one. zones. Biologically infuenced corrosion of concrete in big In the manufacture of concrete class B45, B60, and B70 cities has most ofen been detected in building foundations (V 600, V 800, and V 1000) based on Portland cement and walls. Taken into account the absence of direct contacts PC500, Melfux 2651 F superplasticizer (BASF Construction of the city buildings with groundwater and low winter Polymers)wasaddedinanamountof0.5%byweightof temperatures, the role of nonsporeforming and sporeforming cement (Mordovcement, Russia). Te water/cement ratio was but thermophilic sulfate-reducing bacteria (genus Desulfo- 53/100. For universality of notation, hereinafer we use the tomaculum) in destruction of houses is minimal. Te basic term “cement” for all samples. Te strength of concrete is destructors in this area are micromycetes synthesizing broad specifed by the marks denoted by the Latin letter “M” and spectrum of organic acids which can be extremely aggressive by numbers from 400 to 1000, depending on the amount to concrete [10]. Moreover, production of secondary metabo- of cement used in a mix and indicating the compressive 2 lites (antibiotics, mycotoxins) gives them an advantage in the strength in kg/cm . Te prepared sterile beams were placed concrete colonization over bacteria. in containers presterilized with 70% ethanol (Figure 1(a)). Our study is aimed at isolation and identifcation of fla- Containers were flled with a sterile medium, and spores of 5 mentous fungi growing on the concrete walls of old buildings dominant micromycetes (10 /ml) were added (Figures 1(b) in Kazan city (Tatarstan, Russia) and characterization of their and 1(c)). Control container was flled by sterile Czapek-Dox destructive properties based on the measurement of growth medium without inoculation. Te lower part of the beams up rate and acid production, for the future assessment of deterio- to a height of 2 cm was immersed in the medium; the upper ration level of fne-grained concrete induced by them. Apply- part was in the humid atmosphere of the closed containers ∘ ing an integrated approach combining methods of microbi- which were incubated at 30 Cduring28days. ology with standard methods for determining the strength of building structures, we justifed the connection between .. Organic Acids Analysis. Cultural fuid of 18 fungal isolates the decrease of concrete strength and the level of fungal growing 5 days up to the end of exponential phase on metabolic activity whose main markers were production of liquid Czapek-Dox medium was analyzed on the production organic acids, radial growth rate, and antagonistic activity. of secreted organic acids using a high-performance liquid chromatograph Flexar (PerkinElmer, USA). Te separation 2. Materials and Methods of organic acids was carried out in a Brownlee Analytical C18 (150 × 4.6 mm) column packed with 3 �mparticles. .. Micromycetes. Te microscopic fungi were isolated from Te elution was carried out at room temperature in a linear the inner wall surface of the former military hospital in Kazan gradient using a system consisting of a solution of 10 mM city (Tatarstan, Russia). Te surface of the concrete wall with KH2PO4 adjusted with orthophosphoric acid to pH 2.4 visible growth of micromycetes at 10 diferent sites was treated (eluent A) and acetonitrile (eluent B).Te fow rate of the with a sterile cotton swab, which was then placed in a tube mobile phase was 1 ml/min. Peaks were identifed using a UV with 5 ml of sterile water. From there, 10 samples of 100 ml detector at 210 nm [12]. As standards, acid solutions were used (in triplicates) were applied to a solid Czapek-Dox medium (g/l): oxalic (0.15), tartaric (0.35), malic (0.5), lactic (0.35), ∘ in Petri dishes, which were incubated for 5 days at 30 C. citric (0.5), and acetic (0.15). Te morphology of colonies was analyzed microscopically. Total number of isolates was 18. Te dominant fungi of the .. Determination of Micromycete Radial Growth Rate. Te genera Aspergillus and Penicillium were used to study their rapid growth rate of fungi is connected with the production destructive properties. For the cultivation of micromycetes, of organic acids as primary metabolites. To found the most a liquid and agarized

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