Assessment of Biofilm Inhabitants of Deteriorated Surfaces of Heritage Sites

Abstract

Heritage monument surfaces are being deteriorated by diverse microbiota. This study used culture-dependent and culture-independent strategies to investigate the bacterial inhabitants colonizing India's two different heritage sites, namely Chhatrapati Shivaji Maharaj Terminus (CSMT) Mumbai and Ajanta Caves (AJC), Aurangabad. The culturable approach showed the presence of common environmental bacteria such as Pseudomonas and Bacillus. However, 16S rRNA gene amplicon sequencing of the composite samples revealed rich bacterial diversity in the AJC metagenome compared to CSMT, which is comparatively well maintained. The functional profile of metagenomes revealed abundant hits for sulfate reducers (15.4%; 29.8%) and nitrate reducers (36.3%; 25.1%), respectively, in CSMT and AJC. Biofilm-associated genes (alg1 and pelA) were detected in metagenomic DNA and cultivated bacterial genomic DNA to envisage the presence of biofilm formers dwelling on the heritage surfaces. The study suggests the possibility of tracking the biofilm bacteria inhabiting the deteriorated surfaces of heritage sites through an integrated approach that would provide risk assessment toward management and conservation strategies.

Keywords:

• Biofilms
• gene tracking
• heritage sites
• 16S rRNA gene amplicon sequencing

Acknowledgments

The authors thank CSIR-NEERI; Nagpur for providing the necessary infrastructure facilities. The manuscript was checked for plagiarism using i-Thenticate software at the NEERI Knowledge Resource Centre: KRC No: NEERI/KRC/2020/APRIL/EBGD/2

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data supporting this study’s findings are available from the corresponding author (AQ) upon reasonable request.

Additional information

Funding

The authors acknowledge CSIR-India for providing financial support for the above study as part of CSIR Mission Mode project Vertical II entitled ‘Conservation and Restoration of Heritage structures’ (Project HCP-0018/5.2.1).