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Microbial communities associated with corals are an important source of bioactive metabolites with great potential for drug discovery. However, culturing these symbiotic microbes is extremely complex and often impossible. In toto coral aquaculture performed ex situ (the culture of the holobiont–cnidarian host and associated microorganisms) has been suggested as a potential solution to solve the constraints of supplying metabolite biomass to fuel the drug discovery pipeline. In the present study we investigated if coral fragmentation and different light intensities (photosynthetically active radiation (PAR) of 50, 80 and 120 μmol quanta m − 2 s − 1 ) significantly affect the diversity and structure of the microbial communities present in the leather coral Sarcophyton cf. glaucum assessed through polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). The diversity and structure of the bacterial communities present in mother colonies and fragments stocked under identical conditions remained stable two months post fragmentation, as well as between coral fragments stocked under different PAR intensities. The observed stability in the microbial community supports that in toto coral aquaculture may be a suitable option to produce metabolite biomass from symbiotic microorganisms. The possibility to employ a low PAR intensity to grow coral fragments without significantly affecting their microbial diversity and structure is likely to decrease aquaculture production costs and improve its economic viability.

In this study, determination of heavy metal parameters and microbiological characterization of marine sediments obtained from two heavily polluted sites and one low-grade contaminated reference station at Jiaozhou Bay in China were carried out. The microbial communities found in the sampled marine sediments were studied using PCR-DGGE (denaturing gradient gel electrophoresis) fingerprinting profiles in combination with multivariate analysis. Clustering analysis of DGGE and matrix of heavy metals displayed similar occurrence patterns. On this basis, 17 samples were classified into two clusters depending on the presence or absence of the high level contamination. Moreover, the cluster of highly contaminated samples was further classified into two sub-groups based on the stations of their origin. These results showed that the composition of the bacterial community is strongly influenced by heavy metal variables present in the sediments found in the Jiaozhou Bay. This study also suggested that metagenomic techniques such as PCR-DGGE fingerprinting in combination with multivariate analysis is an efficient method to examine the effect of metal contamination on the bacterial community structure.