Development, evaluation and valorization of novel plant origin materials for the cleaning- protection of caves belonging to the cultural inheritage of Greece co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH-CREATE-INNOVATE (project code: T1EDK- 05264)


The proposal concerns the confrontation of the serious problem of interior alteration observed in ALL caves of the country (about 200) due to the development of various microorganisms. This phenomenon has as direct consequence the significant aesthetic and functional degradation of the caves. Literature results have indicated that the organisms normally grown in these cases are non-photosynthetic (eg Proteobacteria, Actinobacteria, Firmicutes, Radiobacteria, Saprotrophic fungi and yeasts) and/or photosynthetic (photosynthetic microflora) visible as green or dark (brown or black) stains on their walls and ground. The photosynthetic microflora is mainly developed in tourist caves because of their electrification with prevailing the prokaryotic cyanobacteria, along with eukaryotic micro-algae such as chlorophyll, diatoms.

The hitherto practice for tackling the problem refers to the use of aqueous solutions of chemical bleaches (mainly chlorinated derivatives), whose application is connected with the temporary ban of cave visiting (at least for three months), affecting negatively to their financial outcome.

Main subject of the proposal is to address the above problems by replacing chemical bleaches with herbal biocides. For this purpose, a series of essential oils and hydrosols (by-products of the of plant materials hydrodistillation) from plants of the Greek flora containing known bioactive molecules such as carvacrol, thymol, mycene etc. that are known to display significant activities against bacteria, fungi and microalgae will be tested and evaluated. In addition, hydrolysols have been found to possess significant activity against the formation and existence of biofilms. It is evident that the use of herbal solutions from edible plants is not expected to affect negatively the environment and does not require the ban of cave visiting. Finally, an additional advantage connected with the use of such preparations is associated with the expected non-development of bacteria and cave fungi as a result of the considerable diversity of their phytochemicals.

The project implementation methodology includes a series of industrial research actions. Specifically, the isolation-chemical characterization of at least 15 essential oils and hydrosoles (in laboratory level 2-5 mL) of plants from the Greek flora will be carried out and their chemical content will be determined. Then, the evaluation of their activity micro-organisms of the photosynthetic (and non-microflora) and their toxicity will be follow and the three best natural cave cleaners will be selected in respect the following criteria: 1. Activity, 2. Toxicity, 3. Availability, 4. Price. The three best candidates will be produced in a large scale and then diffused in nontoxic emulsifiers to achieve the best results in respect their dispersion in the aqueous solution of the cleanser and the size of the emulsion droplets for maximizing their effects. Finally, their pilot scale implementation in at least two caves will provide the most active, which will be selected for use after its MSDS and environmental impacts evaluation.

The project will be completed by the patent certification of the activity and uses of the product, bringing to the market an innovative product that will be a first entrance for this category, with significant prospects for commercial exploitation in Greece and abroad.