The influence of biotic and abiotic factors on the rate of degradation of poly(lactic) acid (PLA) coupons buried in compost and soil

Since ages, architects and artists worldwide have focused on usage of durable stones as marble and limestone for construction of beautiful and magnificent historic monuments as European Cathedrals, Roman and Greek temples, Taj Mahal etc. But survival of these irreplaceable cultural and historical assets is in question these days due to their degradation and deterioration caused by number of biotic and abiotic factors. These causative agents have affected not only the aesthetic appearance of these structures, but also lead to deterioration of their strength and durability. The present review emphasizes about different causative agents leading to deterioration and application of microbially induced calcium carbonate precipitation as a novel and potential technology for dealing with these problems. The study also sheds light on benefits of microbial carbonate binders over the traditional agents and future directions.

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Application of calcifying bacteria for remediation of stones and cultural heritages

Essential oils (EOs) have been known for a long time, and they are used in several fields such as medicine and aromatherapy, as well as in the food and pharmaceutical industries. In the last decade, EOs have also been applied to contrast the biodeterioration of cultural heritage, representing a powerful resource in green conservation strategies. In this study, an integrated approach based on microscopic observation, in vitro culture, and molecular investigation was preliminarily employed to identify biological systems colonizing wooden artworks. In order to contrast the biodeterioration processes induced by fungal colonization (Aspergillus flavus) or insect infestation (Anobium punctatum), wooden artworks were exposed to the volatile compound of Origanum vulgare or Thymus vulgaris essential oils (EOs), the chemical composition of which was determined by GC-MS using both polar and apolar columns. Artwork exposure was performed in ad-hoc-assembled "clean chambers." Evaluating the effects on biological systems, the compatibility with artwork constitutive materials, and the lack of negative effects on human health and environmental pollution, the use of EOs as a valid alternative to traditional biocides must be considered.

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Essential Oils as Natural Biocides in Conservation of Cultural Heritage

Limestone biodeterioration: A review on the Portuguese cultural heritage scenario

Geochemical cycles result in the chemical, physical, and mineralogical modification of rocks, eventually leading to formation of soil. However, when the stones and rocks are a part of historic buildings and monuments, the effects are deleterious. In addition, microorganisms also colonize these monuments over a period of time, resulting in formation of biofilms; their metabolites lead to physical weakening and discoloration of stone eventually. This process, known as biodeterioration, leads to a significant loss of cultural heritage. For formulating effective conservation strategies to prevent biodeterioration and restore monuments, it is important to know which microorganisms are colonizing the substrate and the different energy sources they consume to sustain themselves. With this view in scope, this review focuses on studies that have attempted to understand the process of biodeterioration, the mechanisms by which they colonize and affect the monuments, the techniques used for assessment of biodeterioration, and conservation strategies that aim to preserve the original integrity of the monuments. This review also includes the “omics” technologies that have started playing a large role in elucidating the nature of microorganisms, and how they can play a role in hastening the formulation of effective conservation strategies.

Microbial Biodeterioration of Cultural Heritage: Events, Colonization, and Analyses

Since ancient time, magnificence and beauty have been the goals of architecture. Artists and architects used high strength, durable and beautiful stones like marble and limestone for the construction of monuments like Taj Mahal, Milan Cathedral, Roman Catacombs and Necropolis in Rome etc. These historic monuments are exposed to open air which allows the invading army of algae, cyanobacteria, fungi etc. to easily access them. The invasion of microorganisms and their subsequent interaction with mineral matrix of the stone substrate under varied environment conditions fosters deterioration of stones by multiple mechanisms resulting in loss of strength, durability, and aesthetic appearance. The review details about the major routes and mechanisms which led to biodeterioration, discusses current remedial methodologies and suggests future directions.

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Microbially induced deterioration of architectural heritages: routes and mechanisms involved

Over the last few decades there has been increasing global concern over the deterioration of historical monuments and stone works of art It has posed a big challenge for the archaeologist, geobiologists and bioconservators and consequently encouraged the search for developing novel preventive and remedial methodologies for safeguarding these sculptural monuments and stone works of art Many conventional methods which rely on use of physical and chemical treatments have been applied but none of them have yielded satisfactory results Recently, bioconservation and consolidation methods employing carbonatogenic microbes have received much attention These microorganisms can precipitate calcium carbonate and, thereby, confer protection to historic monuments Riassunto Negli ultimi decenni c’e stata una crescente preoccupazione a livello mondiale per quel che concerne il deterioramento dei monumenti storici e dei manufatti lapidei Questa rappresenta una grande sfida per gli archeologi, geo-biologi e bioconservatori che ha promosso la ricerca e lo sviluppo di nuove metodologie preventive e di recupero finalizzate alla salvaguardia di questi monumenti e opere d’arte scultoree in pietra Molti metodi convenzionali che si basano sull’uso di trattamenti fisici e chimici sono stati applicati, ma nessuno di essi ha dato risultati soddisfacenti Recentemente, hanno destato molta attenzione i metodi di bioconservazione e consolidamento che impiegano la carbonato-genesi da microrganismi Questi sono in grado di indurre la precipitazione di carbonato di calcio e, quindi, conferire protezione ai monumenti storici Resume Dans ces dernieres decennies, il y a eu une croissante preoccupation au niveau mondial concernant la deterioration des monuments historiques et des ouvrages de pierre Elle represente un grand defi pour les archeologues, les geo-biologistes et les bio-conservateurs et a promu la recherche et le developpement de nouvelles methodologies preventives et de recuperation finalisees a la sauvegarde de ces monuments et œuvres d’art sculpturales en pierre De nombreuses methodes conventionnelles qui se basent sur l’usage de traitements physiques et chimiques ont ete appliquees, mais aucune d’elles n’a donne de resultats satisfaisants Recemment, les methodes de bioconservation et consolidation qui emploient la carbonatogenese de micro-organismes ont suscite beaucoup d’attention Elles sont en mesure d’induire la precipitation de carbonate de calcium et, donc, de conferer une protection aux monuments historiques Zusammenfassung Der Verfall historischer Denkmaler und von Steinarbeiten sorgte in den vergangenen zehn Jahren weltweit fur wachsende Besorgnis Fur Archaologen, Geobiologen und Bio-Konservatoren stellt diese Situation eine grose Herausforderung dar und fungiert als Ausgangspunkt fur die Erforschung und Entwicklung neuer vorbeugender und rekuperativer Methodiken zum Schutz dieser Denkmaler und Steinskulpturen Viele bisher angewendete und auf physischen sowie chemischen Behandlungen beruhende Verfahren brachten keine zufriedenstellenden Ergebnisse In der letzten Zeit stiesen in der Biokonservation und Befestigung angewandte Methoden auf groses Interesse, die auf der Karbonatgenese durch Mikroorganismen beruhen Diese Verfahren sind in der Lage, die Ausfallung von Kalziumkarbonat herbeizufuhren und somit Denkmalern einen Schutz zu verleihen Resumen En las ultimas decadas hubo una creciente preocupacion a nivel mundial por lo que se refiere al deterioro de los monumentos historicos y de las obras lapideas Se trata de un gran desafio para los arqueologos, geo-biologos y bioconservadores que ha promovido la investigacion y el desarrollo de nuevas metodologias preventivas y de recuperacion encaminadas a proteger estos monumentos y las obras de arte escultoricas en piedra Se han aplicado muchos metodos convencionales basados en el uso de tratamientos fisicos y quimicos, pero ninguno de ellos ha logrado resultados satisfactorios De reciente, han suscitado mucha atencion los metodos de bioconservacion y consolidacion basados en la genesis del carbonato desde microrganismos Siendo capaces de inducir la precipitacion del carbonato calcico, estos microorganismos pueden proteger los monumentos historicos Резюме В последние десятилетия во всем мире заметно возрастает тревога по поводу упадка исторических памятников и каменных артефактов Это большой вызов археологам, геобиологам и биоконсерваторам, который дал начало поиску и развитию новых предохранительных и восстановительных методологий, направленных на сбережение этих памятников и каменных скульптур Многие традициональные методы, основанные на использовании физических и химических процедур, были применены, но никакой из них не дал удовлетворяющих результатов В последнее время вызывают большой интерес методы биоконсервации и консолидации, которые используют генезиз карбонатов из микроорганизмов Они способны вызывать осаждение карбоната кальция и, следовательно, обеспечивать защиту исторических памятников Ամփոփում Վերջին տասնամյակների ընթացքում աճող մտահոգություն է եղել աշխարհում պատմական հուշարձանների եւ քարարաշեն արտեֆակտների վատթարացման վերաբերյալ Սա մեծ մարտահրավեր է հնագետների, կենսաբանների ու բիոկոնսերվատորների համար, որը նպաստել է հետազոտման եւ զարգացման նոր մեթոդները օգտագործել կանխարգելիչ եւ վերականգնման նպատակով այդ հուշարձանների եւ քարի վրա քանդակված արվեստի գործերի պահպանությանը: Շատ մեթոդներ, որոնք հիմնված են ֆիզիկական եւ քիմիական տեխնիկայի վրա չեն տվել բավարար արդյունք: Վերջերս, մեծ ուշադրություն է գրավել բիոկոնսերվացիան ու ամրապնդումը օգտագործելով միկրոօրգանիզմների կողմից կարբոնատ-ծնող մեթոդներ: Դրանք կարող են առաջացնել կալցիումի կարբոնատի տեղումներ  եւ, հետեւաբար, ուժեղացնել պատմական հուշարձանների պաշտպանությունը:

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Swaranjit Singh Cameotra

Papers

Microbially induced deterioration of architectural heritages: routes and mechanisms involved

Carbonatogenesis: microbial contribution to the conservation of monuments and artwork of stone